*Article* **Efficient Synthesis of 2-OH Thioglycosides from Glycals Based on the Reduction of Aryl Disulfides by NaBH4**

**Yang-Fan Guo †, Tao Luo †, Guang-Jing Feng, Chun-Yang Liu and Hai Dong \***

Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry & Chemical Engineering, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan 430074, China

**\*** Correspondence: hdong@mail.hust.edu.cn

† These authors contributed equally to this work.

**Abstract:** An improved method to efficiently synthesize 2-OH thioaryl glycosides starting from corresponding per-protected glycals was developed, where 1,2-anhydro sugars were prepared by the oxidation of glycals with oxone, followed by reaction of crude crystalline 1,2-anhydro sugars with NaBH4 and aryl disulfides. This method has been further used in a one-pot reaction to synthesize glycosyl donors having both "armed" and "NGP (neighboring group participation)" effects.

**Keywords:** glycals; 2-OH thioglycosides; glycosyl donors; glycosylation; one-pot reaction
