Solvent-Dependent Mechanism and Stereochemistry of Mitsunobu Glycosylation with Unprotected Pyranoses
作者:Hironori Takeuchi、Yusuke Fujimori、Yoshihiro Ueda、Hiromitsu Shibayama、Masaru Nagaishi、Tomoyuki Yoshimura、Takahiro Sasamori、Norihiro Tokitoh、Takumi Furuta、Takeo Kawabata
DOI:10.1021/acs.orglett.0c01549
日期:2020.6.19
acidic glycosyl acceptors such as carboxylic acids, phenols, and imides, retaining its high stereoselectivity (33 examples). Glycosylation of a carboxylic acid with unprotected α-d-mannose proceeded also in an SN2 manner to directly afford a usually less accessible 1,2-cis-mannoside. One- or two-step total syntheses of five simple natural glycosides were performed using the glycosylation strategy presented
在Mitsunobu条件下,在二恶烷中,用未保护的α- d-葡萄糖对苯甲酸高度立体选择性糖基化提出了一种S N 2机制,而在DMF中,对于非立体选择性糖基化则提出了一种S N 1机制。S N 2型立体选择性Mitsunobu糖基化通常可作为糖基供体与多种酸性糖基受体(如羧酸,酚和酰亚胺)结合使用,作为糖基供体,适用于各种未保护的吡喃糖,保持其高立体选择性(33个例子)。羧酸与未保护的α- d-甘露糖的糖基化也以S N 2方式进行,以直接提供通常较难获得的1,2-顺式-甘露糖苷。使用未保护的α- d-葡萄糖,使用此处介绍的糖基化策略进行五个简单天然糖苷的一步或两步总合成。