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Biomedical subjects

Yu Zhao

Publications and source records attributed to Yu Zhao.

At least 19 recordsLinked to original sources

Conventional and Shared Genetic Association Analysis Between Diabetes Mellitus and Sensorineural Hearing Loss.

PURPOSE: This study aims to investigate the epidemiological and genetic associations between diabetes mellitus (DM) and sensorineural hearing loss (SNHL) across different subtypes. METHODS: We analyzed 502,490 participants from the UK Biobank using multivariate logistic regression to examine the association between DM and SNHL, considering gender, age, and HbA1c levels. Genetic correlations and causality were examined by linkage disequilibrium score regression and bidirectional Mendelian randomization. Cross-trait meta-analyses identified shared loci between DM and SNHL, followed by gene annotation, functional analysis, and drug candidate exploration for the shared traits. RESULTS: Observational analysis revealed significant associations between DM and SNHL, consistent in subgroups based on age, sex, and certain HbA1c levels. A positive genetic correlation was found between type 2 diabetes mellitus (T2D) and SNHL (Rg = 0.0982, p = 0.0095) between T2D and SNHL, and four loci were identified, with ARHGEF28 and TCF7L2 prioritized as credible pleiotropic genes. Enrichment was indicated in glucose metabolism and organogenesis, with shared heritability in metabolic tissues and outer hair cells. Metformin was identified as potential drug candidates for the T2D-SNHL comorbidity. CONCLUSION: These findings progress our understanding of the epidemiological association, shared genetic basis, and potential therapeutic targets between T2D and SNHL, which might contribute to the management of their comorbidity.

Humans↗

Genetically Proxied Inhibition of Cholesterol-Lowering Drug Targets and Survival in HPV-Positive and Non-HPV-Driven Head and Neck Cancer: A Multicentre MR Study.

BACKGROUND: Cholesterol pathways may influence head and neck squamous cell carcinoma (HNSCC) progression, but evidence on prognosis is inconsistent. We used Mendelian randomization (MR) to test whether genetically proxied inhibition of major low-density lipoprotein cholesterol (LDL-C)-lowering drug targets and circulating lipid traits affects overall survival (OS) in HPV-positive and non-HPV-driven HNSCCs. METHODS: We proxied lifelong LDL-C lowering using 55 cis-acting single-nucleotide polymorphisms in HMGCR, NPC1L1, PCSK9, and LDL-receptor (LDLR) from the updated 2021 Global Lipids Genetics Consortium and instrumented circulating lipid traits. Two-sample MR estimated effects on OS in 4,869 multicentre HNSCC cases (1,291 HPV-positive; 3,578 non-HPV-driven) using minimally adjusted Cox models. Sensitivity analyses additionally adjusted for tumor stage and treatment, assessed collider bias using an external HNSCC incidence genome-wide association study, and examined between-center heterogeneity and colocalization. RESULTS: Using the updated Global Lipids Genetic Consortium 2021 instruments, genetically proxied HMGCR inhibition showed a directionally protective but nonsignificant association with OS in HPV-positive oropharyngeal HNSCC in the primary analysis [inverse variance weighted (IVW) HR = 0.19; 95% confidence interval (CI), 0.03-1.18; P = 0.08], with directionally concordant weighted median results. No corresponding protective association was observed for HMGCR in non-HPV-driven disease (IVW HR = 1.68; 95% CI, 0.78-3.63; P = 0.19). No clear evidence of association was observed for NPC1L1, PCSK9, LDLR, or circulating lipid traits in either HPV stratum. Colocalization did not support a shared causal variant. CONCLUSIONS: These analyses provide suggestive evidence that genetically proxied HMGCR inhibition may influence survival in HPV-positive oropharyngeal HNSCC. IMPACT: HMGCR-related pathways may be relevant to prognosis in HPV-positive oropharyngeal HNSCC, whereas clear survival effects of other cholesterol-lowering targets were not supported.

Humans↗

Study on the mechanism of SW inhibiting testosterone synthesis in mouse Leydig cells.

BACKGROUND: Swainsonine (SW), the main toxic component of locoweed, can cause livestock poisoning and reproductive damage in male animals; however, the mechanism by which it affects testosterone secretion remains unclear. METHODS: Ten-week-old male C57BL/6 mice were orally administered SW at doses of 0, 0.05, and 0.25 mg/(kg·d) for 28 days. TM3 mouse Leydig cells were treated with SW at concentrations of 0, 1, and 10 nM for 24 h. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed on RNA-seq data from mouse testicular tissues to identify differentially enriched pathways between the control and SW-treated groups. Testosterone secretion levels were measured using an enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of steroidogenesis-related genes (StAR, Cyp11a1, Hsd3b2, and Hsd17b3) were detected by qPCR, while the expression of the steroidogenic acute regulatory (STAR) protein was detected by western blotting. AutoDock Vina molecular docking was used to predict the binding affinity between SW and the STAR protein. RESULTS: KEGG analysis revealed a significant enrichment of pathways related to steroid synthesis. In both the mouse model and TM3 cells, SW significantly inhibited testosterone secretion, downregulated the mRNA expression of StAR, Cyp11a1, Hsd3b2, and Hsd17b3, and reduced the protein expression of STAR. Molecular docking analysis revealed multiple potential hydrogen-bond interaction sites between SW and STAR. CONCLUSION: SW downregulates the expression of steroidogenesis-related genes and STAR protein, thereby suppressing testosterone secretion in male mice and TM3 cells.

Swainsonine↗

Genomic insights into Aeromonas infections in diarrheal patients: high diversity, emerging resistance, and potential outbreak in Beijing.

BACKGROUND: Aeromonas species are ubiquitous aquatic bacteria that have emerged as significant foodborne enteric pathogens worldwide, yet their genomic landscape in clinical settings remains poorly delineated, particularly in Beijing. METHODS: To address this gap, we performed active surveillance for Aeromonas among 691 consecutive diarrheal outpatients in a Beijing district from January to December 2024. Isolates were recovered using enrichment culture coupled with PCR screening and identified by MALDI-TOF MS. Antimicrobial susceptibility was tested against 17 agents. Whole-genome sequencing was conducted on all isolates, enabling average nucleotide identity (ANI) analysis, comprehensive annotation of antimicrobial resistance and virulence genes, multilocus sequence typing (MLST), and core-genome SNP (cgSNP)-based phylogenetics. RESULTS: Aeromonas was detected in 3.3% (23/691) of patients, with Aeromonas veronii (56.52%, 13/23) and Aeromonas caviae (26.09%, 6/23) predominating. Co-infections with other enteric pathogens occurred in 65.2% of positive cases. Resistance rates were notably high for ampicillin/ampicillin-sulbactam (78.26%), nalidixic acid (56.52%), and ertapenem (21.73%), and 65.21% of isolates were multidrug-resistant. Genotypic-phenotypic concordance was robust, with β-lactamase genes ampS (60.87%) and blaCEPH-A3 (47.83%) being most prevalent. Strikingly, mcr-3.25 and mcr-3.3, which belong to the mcr family (originally described as mobile colistin resistance genes), were identified in 8.70% of isolates, exhibiting perfect correlation with phenotypic resistance. Plasmer analysis suggested both mcr genes to be chromosomally encoded. Comparative genomic analysis of virulence-associated genes revealed striking species-specific specialization: A. veronii predominantly carried complete T3SS clusters (61.5%), A. caviae and Aeromonas enteropelogenes were enriched in T6SS genes, and a single A. dhakensis isolate possessed an extensive arsenal including T3SS, T6SS, and a full RTX toxin cluster. MLST resolved the 23 isolates into 22 sequence types, 18 of which were novel. Phylogenetic reconstruction identified a tight monophyletic cluster of three A. veronii isolates (9-27 SNP differences) recovered within a 96-h window, suggestive of a potential cluster that warrants further epidemiological investigation. Comparative genomic analysis of the rare species Aeromonas allosaccharophila demonstrated that the Beijing clinical isolate S14 differs from the U.S. clinical strain ATCC 35942 by 42,099 SNPs, confirming its distinct genetic lineage. CONCLUSION: Collectively, this study delineates high genetic diversity, emerging chromosomal colistin resistance, and species-specific virulence specialization among Aeromonas isolates from diarrheal patients in Beijing. The detection of a potential outbreak cluster and a rare clinical isolate underscores the power of genomics-based surveillance for detecting and mitigating foodborne pathogen threats.

Aeromonas↗

Integrative machine learning and transcriptomic analysis reveals molecular mechanisms underlying low survival rate in larval Chinese Bahaba (Bahaba taipingensis).

Chinese Bahaba (Bahaba taipingensis) is a Class I protected marine fish endemic to China. Low larvae survival during artificial breeding severely hinder population recovery. To investigate the molecular mechanism of high mortality in larval fish, this study performed RNA-seq on liver from naturally deceased (ND) and mass-dead (MD) individuals, combined with least absolute shrinkage and selection operator (LASSO) regression and random forest (RF) algorithms to screen for core signature genes. A total of 873 differentially expressed genes (DEGs) were identified, including 112 upregulated and 761 downregulated genes. GO and KEGG enrichment analyses revealed significant enrichment in amino acid metabolism disorders, one‑carbon folate pool impairment, PPAR signaling abnormalities, ECM-receptor interaction, focal adhesion pathway, indicating widespread metabolic suppression accompanied by extracellular matrix remodeling and signaling disturbances in the livers of MD fish. MAD pre-filtering combined with dual machine learning algorithms yielded 18 robust core signature genes, among which SLC38A4, MMP1, FADD, FKBP5, and APOB were consistently identified as high-frequency core genes by both algorithms. SLC38A4 exhibited the highest importance score in the RF model and was significantly downregulated, making it the primary molecule distinguishing ND from MD phenotypes. ROC curve analysis showed that both models achieved an AUC of 1.000 (95% CI lower bound: 0.610), confirming the precise discriminatory ability of the core genes. GSEA further demonstrated significant enrichment of this core gene set in ND samples. This study provides the first systematic elucidation of the molecular mechanisms underlying liver dysfunction in low survival rate B. taipingensis, characterized by amino acid transport impairment, metabolic reprogramming, and structural remodeling, offering theoretical foundations for health assessment, early mortality risk warning, and artificial breeding conservation of this species.

Animals↗

Divergent evolutionary strategies in spider venoms: A comparative proteomic profiling of four sympatric species from Yunnan.

Spider venoms comprise complex cocktails of bioactive molecules evolved for predation and defense, representing a valuable resource for biological research and pharmaceutical discovery. In this study, we performed a systematic analysis of venom gland extracts from four common spider species indigenous to Yunnan, China: Agelena limbata, Hippasa lycosina, Lycosa grahami, and Sinopoda pengi. Using an integrated transcriptomic and proteomic targeted profiling approach, we successfully annotated 141 distinct toxins. Comparative analysis revealed significant interspecific heterogeneity, suggesting distinct evolutionary trajectories and "weapon system economics." Both A. limbata and L. grahami exhibited a "peptide-dominant" profile anchored by neurotoxic peptides and isomerases, optimized for rapid chemical paralysis. In contrast, S. pengi displayed a distinct "protein-dominant" signature enriched with high-molecular-weight enzymes and CAP superfamily proteins, likely functioning to facilitate tissue degradation and toxin diffusion. Occupying an intermediate position, H. lycosina demonstrated a hybrid composition. These findings suggest that although these species share the same geographical range, their venom systems have undergone divergent evolutionary adaptations driven by specific ecological niches and hunting strategies. This study represents the first systematic proteomic characterization of these venom components, providing a valuable reservoir of molecular candidates while highlighting the bioinformatic nuances of analyzing whole-gland homogenates.

Animals↗

Przewalskin B, a novel diterpenoid with an unprecedented skeleton from Salvia przewalskii maxim.

Przewalskin B (1), a novel diterpenoid possessing a unique skeleton, was isolated from a Chinese medicinal plant Salvia przewalskii. Its structure and relative stereochemistry were elucidated by extensive NMR analysis and a single-crystal X-ray study. A possible biosynthetic pathway for 1 was proposed. Compound 1 exhibited modest anti-HIV-1 activity with EC50 = 30 microg/mL. [structure: see text].

Anti-HIV Agents↗

Using case vignettes to measure HIV-related stigma among health professionals in China.

BACKGROUND: We examined Chinese health professionals' attitudes towards patients with AIDS vs patients with hepatitis B. METHODS: A representative sample of 1101 Chinese health professionals was used. Prejudicial attitudes and willingness to interact were measured based on two case vignettes. RESULTS: Statistical analyses revealed that health professionals had negative biases against acquired immunodeficiency syndrome (AIDS) patients and reported much less willingness to interact with AIDS patients than hepatitis B patients. Perceived risk of infection at work was also negatively associated with willingness to interact with patients with human immunodeficiency virus (HIV)/AIDS, but relationships varied by profession. CONCLUSIONS: This study underscores the importance of developing and implementing stigma reduction interventions in health care settings to address attitudinal biases and discrimination in clinical practice.

Acquired Immunodeficiency Syndrome↗

Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants.

Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C222(1) and diffract to 2.0 A, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 A.

Alcohol Oxidoreductases↗

Synthesis and cytotoxicity of some new eriocalyxin B derivatives.

Eriocalyxin B (1) was regarded as the promising candidate for new anticancer agent because of its potent activity and novel mechanism of action. Systematic modifications of 1 were done, and nineteen derivatives were synthesized and their cytotoxicities against five tumor cell lines were evaluated. The structure-activity relationship (SAR) of 1 confirmed that the alpha,beta-unsaturated ketone moieties in ring A and D are the leading active sites; the 7,20-epoxy moiety, OH-6 and OH-7 play an important role in keeping the cytotoxicity. The 6,7-seco derivative 19 had remarkable activity while derivative 20 oxidized from 19 was completely inactive, which suggested that the carboxyl group could destroy the cytoxicity of 20 despite the presence of alpha,beta-unsaturated ketone moiety.

Antineoplastic Agents↗

Microarray analysis of gene expression in Men1 knockout embryoid body reveals genetic events involved in early mouse embryonic development.

The Men1 gene has been identified as the gene responsible for MEN1, a hereditary syndrome transmitted with an autosomal dominant trait. Disruption of the Men1 gene results in defects of multiple organs development, including the nervous system, heart, liver, cranium, and face. In this study, we used embryoid bodies (EBs) formed from wild-type and Men1-/- ES cells as a model system to investigate effect of Men1 gene on the embryo development. We characterized in detail gene expression profile of these Men1-/- EBs by microarray techniques and identified a series of putative menin targeted genes, including genes involved in development of bone (e.g., Postn, Runx2, and Msx2), liver (e.g., KDR), blood (e.g., Hox9 and Kitl), and pancreatic islet (e.g., Sox4, Foxa1, Btc, Igf2, and Nfatc1). Further studies may shed light onto the underlying mechanisms of the interplay between menin and these genes.

Animals↗

A variant of the HTRA1 gene increases susceptibility to age-related macular degeneration.

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss in the developed world and has a strong genetic predisposition. A locus at human chromosome 10q26 affects the risk of AMD, but the precise gene(s) have not been identified. We genotyped 581 AMD cases and 309 normal controls in a Caucasian cohort in Utah. We demonstrate that a single-nucleotide polymorphism, rs11200638, in the promoter region of HTRA1 is the most likely causal variant for AMD at 10q26 and is estimated to confer a population attributable risk of 49.3%. The HTRA1 gene encodes a secreted serine protease. Preliminary analysis of lymphocytes and retinal pigment epithelium from four AMD patients revealed that the risk allele was associated with elevated expression levels of HTRA1 mRNA and protein. We also found that drusen in the eyes of AMD patients were strongly immunolabeled with HTRA1 antibody. Together, these findings support a key role for HTRA1 in AMD susceptibility and identify a potential new pathway for AMD pathogenesis.

Aged↗

A family with X-linked optic atrophy linked to the OPA2 locus Xp11.4-Xp11.2.

Autosomal dominant optic atrophy (ADOA) is the most common inherited optic atrophy. Clinical features of ADOA include a slowly progressive bilateral loss of visual acuity, constriction of peripheral visual fields, central scotomas, and color vision abnormalities. Although ADOA is the most commonly inherited optic atrophy, autosomal recessive, X-linked, mitochondrial, and sporadic forms have also been reported. Four families with X-linked optic atrophy (XLOA) were previously described. One family was subsequently linked to Xp11.4-Xp11.2 (OPA2). This investigation studied one multi-generation family with an apparently X-linked form of optic atrophy and compared their clinical characteristics with those of the previously described families, and determined whether this family was linked to the same genetic locus. Fifteen individuals in a three-generation Idaho family underwent complete eye examination, color vision testing, automated perimetry, and fundus photography. Polymorphic markers were used to genotype each individual and to determine linkage. Visual acuities ranged from 20/30 to 20/100. All affected subjects had significant optic nerve pallor. Obligate female carriers were clinically unaffected. Preliminary linkage analysis (LOD score = 1.8) revealed that the disease gene localized to the OPA2 locus on Xp11.4-Xp11.2. Four forms of inherited optic neuropathy, ADOA, autosomal recessive optic atrophy (Costeff Syndrome), Leber hereditary optic neuropathy, and Charcot-Marie-Tooth disease with optic atrophy, are associated with mitochondrial dysfunction. Future identification of the XLOA gene will reveal whether this form of optic atrophy is also associated with a mitochondrial defect. Identification of the XLOA gene will advance our understanding of the inherited optic neuropathies and perhaps suggest treatments for these diseases. An improved understanding of inherited optic neuropathies may in turn advance our understanding of acquired optic nerve diseases, such as glaucoma and ischemic optic neuropathy.

Chromosomes, Human, X↗

Comparison of 1-stage versus 2-stage anterior and posterior spinal fusion for severe and rigid idiopathic scoliosis--a randomized prospective study.

STUDY DESIGN: A randomized prospective study. OBJECTIVE: To compare safety, efficacy, and cost between 1-stage and 2-stage anterior and posterior spinal fusion in treating rigid thoracic adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Retrospective study issued different outcomes comparing 1-stage with 2-stage surgical procedures in treating neuromuscular and congenital scoliosis. A randomized prospective study in AIS has rarely been reported. METHODS.: Twenty-four patients were randomly divided into 2 groups. Group A underwent a 2-stage procedure, group B a 1-stage procedure. Inclusion criteria were: (1) AIS; (2) rigid single thoracic curve, > or =90 degrees on anteroposterior and > or =60 degrees on side bending view; and (3) pulmonary function tests, vital capacity > or =500 mL or FEV1 > or =50%. Exclusion criteria were: (1) curves either <90 degrees on anteroposterior or <60 degrees on bending view; and (2) pulmonary function tests, both vital capacity <500 mL and FEV1 <50%. The mean follow up was 3.3 years (range 2-5.1). Clinical outcomes between the 2 groups were analyzed. RESULTS: A statistical t test demonstrated no significant difference in age (P = 0.299), curves on anteroposterior (P = 0.908), on bending (P = 0.905), after surgery (P = 0.699), and at last follow-up (P = 0.946). No significant difference in blood loss (P = 0.089), transfusion (P = 0.334), operation time (P = 0.172), fusion segments anterior (P = 0.161), posterior (P = 0.546), wound drainage (P = 0.557), thoraco drainage (P = 0.948), and loss of correction at follow-up (P = 0.596). However, significant differences were found in length of stay (P < 0.001), patient cost of hospitalization (P < 0.001) between 2 groups, and curve correction (P < 0.001) in each group. Perioperative complications included 1 patient each with pneumonia, pneumothorax (group A), and ileus (group B). Screw nut loosing was found in 1 patient in group B, but no curve deteriorated. No neurologic deficit occurred in either group. CONCLUSION: A comparison of 1-stage versus 2-stage fusion in treating rigid thoracic curves in AIS did not show significant differences in safety or efficacy but did demonstrate significant difference in length of stay and patient cost.

Adolescent↗

Delayed satiety-like actions and altered feeding microstructure by a selective type 2 corticotropin-releasing factor agonist in rats: intra-hypothalamic urocortin 3 administration reduces food intake by prolonging the post-meal interval.

Brain corticotropin-releasing factor/urocortin (CRF/Ucn) systems are hypothesized to control feeding, with central administration of 'type 2' urocortins producing delayed anorexia. The present study sought to identify the receptor subtype, brain site, and behavioral mode of action through which Ucn 3 reduces nocturnal food intake in rats. Non-food-deprived male Wistar rats (n=176) were administered Ucn 3 into the lateral (LV) or fourth ventricle, or into the ventromedial or paraventricular nuclei of the hypothalamus (VMN, PVN) or the medial amygdala (MeA), regions in which Ucn 3 is expressed in proximity to CRF(2) receptors. LV Ucn 3 suppressed ingestion during the third-fourth post-injection hours. LV Ucn 3 anorexia was reversed by cotreatment with astressin(2)-B, a selective CRF(2) antagonist and not observed following equimole subcutaneous or fourth ventricle administration. Bilateral intra-VMN and intra-PVN infusion, more potently than LV infusion, reduced the quantity (57-73%) and duration of ingestion (32-68%) during the third-fourth post-infusion hours. LV, intra-PVN and intra-VMN infusion of Ucn 3 slowed the eating rate and reduced intake by prolonging the post-meal interval. Intra-VMN Ucn 3 reduced feeding bout size, and intra-PVN Ucn 3 reduced the regularity of eating from pellet to pellet. Ucn 3 effects were behaviorally specific, because minimal effective anorectic Ucn 3 doses did not alter drinking rate or promote a conditioned taste aversion, and site-specific, because intra-MeA Ucn 3 produced a nibbling pattern of more, but smaller meals without altering total intake. The results implicate the VMN and PVN of the hypothalamus as sites for Ucn 3-CRF(2) control of food intake.

Amygdala↗

Przewalskin A: A new C23 terpenoid with a 6/6/7 carbon ring skeleton from Salvia przewalskii maxim.

Przewalskin A (1), a novel C23 terpenoid with a 6/6/7 carbon ring skeleton, was isolated from Salvia przewalskii. Its structure was determined by comprehensive 1D NMR, 2D NMR, and MS spectroscopic analysis and subsequently confirmed by a single-crystal X-ray diffraction study of its PDC oxidation derivative (2). Compounds 1 and 2 showed modest anti-HIV-1 activity with EC50 = 41 and 89 microg/mL, respectively.

Carbon↗

Activation of group II metabotropic glutamate receptors attenuates both stress and cue-induced ethanol-seeking and modulates c-fos expression in the hippocampus and amygdala.

Major precipitating factors for relapse to drug use are stress and exposure to drug-related environmental stimuli. Group II (mGlu(2/3)) metabotropic glutamate receptors (mGluRs) are densely expressed within circuitries mediating the motivating effects of stress and drug cues and, therefore, may participate in regulating drug-seeking linked to both of these risk factors. Thus, we tested the hypothesis that pharmacological activation of group II mGluRs modifies both stress- and cue-induced ethanol-seeking, using reinstatement models of relapse. In parallel, brain c-fos expression was examined to identify neural substrates for the behavioral effects of group II mGluR activation. The selective mGlu(2/3) agonist LY379268 (1R,4R,5S,6R-2-oxa-4-aminobicyclo[3.1.0]hexane-4,6-dicarboxylate) (0.3, 1.0, and 3.0 mg/kg, s.c.) dose dependently blocked the recovery of extinguished ethanol-seeking induced by either footshock stress or ethanol-associated discriminative stimuli. These effects were accompanied by modulation of c-fos expression in the hippocampus, central nucleus of the amygdala, bed nucleus of the stria terminalis, and medial parvocellular paraventricular nucleus of the hypothalamus. The results implicate group II mGluRs as a shared neuropharmacological substrate for ethanol-seeking elicited by both drug cues and stress and identify group II mGluRs as promising treatment targets for relapse prevention.

Alcohol Drinking↗

Enantioselective silyl protection of alcohols catalysed by an amino-acid-based small molecule.

Reliable, selective and environmentally friendly chemical transformations are crucial to the development of new therapeutics and the design of novel materials. Chiral catalysts that can be easily prepared and used to obtain organic molecules of high enantiomeric purity are critical to modern chemical synthesis. The development of protecting groups that shield reactive functionalities has also proved indispensable in the preparation of complex biologically active molecules. Here we present a chiral catalyst that promotes the enantioselective protection of a secondary alcohol as one of the most commonly used protected forms of an alcohol: a silyl ether. The catalyst is a small, simple molecule that can be prepared in three steps from commercial materials without the need for rigorously controlled conditions. Enantioselective silylations are performed with commercial silyl chlorides and produce yields of up to 96 per cent at an enantiomeric ratio of up to 98:2. Chiral catalysts for selective formation of commonly used protecting groups such as silyl ethers should significantly enhance the ability of chemical synthesis to deliver, in a more practical and efficient manner, important organic molecules.

Alcohols↗