Asymmetric syntheses of (8R,8aS)- and (8R,8aR)-8-hydroxy-5-indolizidinones: Two promising oxygenated indolizidine building blocks
- 化学化工－已发表论文 
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).