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.
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.
An unexpected yet disciplined course of catalytic Mukaiyama-aldol reaction instead of the expected vinylogous Mukaiyama-aldol reaction has been observed for the reaction of silyloxyfuran with various aldehydes under Lewis acid catalytic control in water-containing solvents.