AuCl3– and AuCl3–Phenylacetylene‐Catalyzed Glycosylations by Using Glycosyl Trichloroacetimidates. Issue 18 (8th May 2015)

• Record Type: Journal Article
• Authors: Roy, Rashmi; Palanivel, Ashok Kumar; Mallick, Asadulla; Vankar, Yashwant D.
• Is Part Of: European journal of organic chemistry. Issue 18(2015)
• Page Start: 4000
• Page End: 4005
• Publication Date: 2015-05-08
• Subjects: Synthetic methods -- Homogeneous catalysis -- Gold -- Glycosylation -- Glycosides -- Carbohydrates -- Amino acids; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201500137
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: Glycosylations of armed and disarmed trichloroacetimidate‐based glycosyl donors were carried out by using the AuCl3 –phenylacetylene relay catalyst system. The effectiveness of this catalytic system was also compared with that of using AuCl3 alone as a catalyst. Glycosylations with these catalysts proceeded efficiently at room temperature within 5–45 min. Excellent diastereoselectivity was obtained for the glycosylation of 2‐ O ‐acetyl‐protected disarmed glycosyl donors, whereas armed glycosyl trichloroacetimidates gave rise to a mixture of anomeric glycosides. Acid‐sensitive nucleophiles such as Fmoc‐serine tert ‐butyl ester or Fmoc‐threonine tert ‐butyl ester successfully underwent the glycosylations, albeit in moderate yields, under mild conditions at room temperature. Abstract : We have reported a convenient room temperature protocol that employs AuCl3 and phenylacetylene as a catalyst system to carry out the glycosylation of glycosyl trichloroacetimidates. The effectiveness of this relay catalyst system was also compared with that of using AuCl3 alone to catalyze the glycosylations.