Asymmetric syntheses of (8R,8aS)- and (8R,8aR)-8-hydroxy-5-indolizidinones:Two promising oxygenated indolizidine building blocks  

作　　者：ZHANG HongKui LI Xin HUANG Huang HUANG PeiQiang 

机构地区：[1]Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen. China

出　　处：《Science China Chemistry》2011年第5期737-744,共8页中国科学（化学英文版）

基　　金：the NSF of China (20672089, 20832005);the NFFTBS (J1030415);the National Basic Research Program of China (973 Program, 2010CB833200)

摘　　要：Starting from the oxygenated piperidine building block 20,two synthetic approaches to new building blocks (8R,8aS)-and (8R,8aR)-8-hydroxy-5-indolizidinones 19a/19b and 15a/15b have been developed,respectively. The first one is based on the trans-diastereoselective reductive alkylation (dr = 93:7),followed by a four-step procedure; and the second one called for the RCM reaction on the N,O-acetal derived from a vinylation,which was followed by a pyrrole formation,and a stereocontrolled cis-selective (dr = 91:9) catalytic hydrogenation. Reduction of the diastereomer 15a produced (8R,8aR)-8-indolizidinol (18).Starting from the oxygenated piperidine building block 20,two synthetic approaches to new building blocks （8R,8aS）-and （8R,8aR）-8-hydroxy-5-indolizidinones 19a/19b and 15a/15b have been developed,respectively. The first one is based on the trans-diastereoselective reductive alkylation （dr = 93：7）,followed by a four-step procedure; and the second one called for the RCM reaction on the N,O-acetal derived from a vinylation,which was followed by a pyrrole formation,and a stereocontrolled cis-selective （dr = 91：9） catalytic hydrogenation. Reduction of the diastereomer 15a produced （8R,8aR）-8-indolizidinol （18）.

关 键 词：INDOLIZIDINES building blocks diastereoselective synthesis RCM reaction catalytic hydrogenation 

分 类 号：O621.34[理学—有机化学] O626.13[理学—化学]