Asymmetric synthesis of alkaloid (–)-(2S,4S) SS 20846 A and its C-4 epimer
Abstract
A diastereoselective intramolecular Mannich reaction using planar chiral iron dienal complexes is employed to prepare optically pure 2,4-disubstituted piperidines. This methodology is applied to the synthesis of natural alkaloids (–)-6 and (–)-7.