Pilocarpine (1) was synthesized in seven steps starting from 2-acetylbutyrolactone. Chirality was introduced by asymmetric reduction of enone 4 and transferred via a Claisen rearrangement. A mild procedure for the preparation of 1,5-disubstituted imidazoles in the last synthetic operation led to pilocarpine unaccompanied by isopilocarpine.
Treatment of ketones or aldehydes with selenium dioxide and diphenyl diselenide in the presence of acid catalyst afforded the corresponding α-phenylselenenyl carbonylcompounds in good yields.
Asymmetric total synthesis of syringolide 1, a nonproteinaceous elicitor
作者:Jun Ishihara、Tetsuya Sugimoto、Akio Murai
DOI:10.1016/s0040-4020(97)10062-x
日期:1997.11
An asymmetric synthesis of syringolide 1, one of the elicitors produced by Pseudomonas syringae pv. tomato, is described. It was synthesized from 2-(1-oxoethyl)-2-buten-4-olide via 1,4-addition of alkenyl cuprate, asymmetric dihydroxylation, and intramolecular Michael reaction.