作者:Tong Li、Tianlu Li、Tongxiao Cui、Yajing Sun、Fengshan Wang、Hongzhi Cao、Richard R. Schmidt、Peng Peng
DOI:10.1021/acs.orglett.8b01446
日期:2018.7.6
Protection of 2,3,4-O-unprotected α-galacto- and α-fucopyranosides with BzCN and DMAP/DIPEA as the base afforded directly and regioselectively the 3-O-unprotected derivatives. The rationale for these studies was to take advantage of the eventual cooperativity of the “cyanide effect” and “the alkoxy group mediated diol effect”. This way, even the totally unprotected α-galactopyranosides could be regioselectively
用BzCN和DMAP / DIPEA作为碱保护2,3,4- O-未保护的α-半乳糖和α-呋喃果糖苷直接和区域选择性地提供了3- O-未保护的衍生物。这些研究的基本原理是利用“氰化物效应”和“烷氧基基团介导的二醇效应”的最终协同作用。这样,甚至完全未保护的α-吡喃半乳糖苷也可以区域选择性地转化为相应的2,4,6- O-保护的衍生物。这些构件的巨大效用已在有效的三糖合成中得到了证明。