A novel approach to the regioselective acylation of spirocyclic C-glucoside of papulacandins
摘要:
A novel approach to the regioselective acylation of spirocyclic C-glucosicle of papulacandins is reported. Conditions were found to effect regioselective acylation of triol 2 to give 2-O-acyl derivatives (5). which after deprotection with TASF afforded exclusively 2-O-acyl derivatives (8). An extensive migration of the acyl group from 2-O- to 3-O-position was observed when the desilylation was conducted with TBAF. These findings provided with a convenient means for extending the SAR of papulacandins at these position. (C) 2002 Elsevier Science Ltd. All rights reserved.
Asymmetric addition of (triisopropylsilyl)acetylene to α,β,γ,δ-unsaturated carbonyl compounds took place in the presence of a cobalt/Duphos catalyst to give the 1,6-addition products in high yields with high regio- and enantioselectivity.
A novel approach to the regioselective acylation of spirocyclic C-glucosicle of papulacandins is reported. Conditions were found to effect regioselective acylation of triol 2 to give 2-O-acyl derivatives (5). which after deprotection with TASF afforded exclusively 2-O-acyl derivatives (8). An extensive migration of the acyl group from 2-O- to 3-O-position was observed when the desilylation was conducted with TBAF. These findings provided with a convenient means for extending the SAR of papulacandins at these position. (C) 2002 Elsevier Science Ltd. All rights reserved.