Highly Stereo- and Regio-Selective Intramolecular Cyclization with Diastereoselective Asymmetric Induction by Electroreduction of Optically Active N-Alkenyl-2-Acylpyrrolidines

Abstract

Electroreduction of optically active (S)- and (R)-N-(3-butenyl)(or (R)-N-benzyl)-2-acetylpyrrolidines (1a) and (1b) (or (2b)) were carried out in N,N-dimethylformamide containing Et₄NOTs as a supporting electrolyte, which brought about highly stereo- and regioselective intramolecular cyclization with diastereoselective asymmetric induction to give the corresponding (4S,5R,6S)- and (4R,5S,6R)-cis-4,5-dimethyl-1-azabicyclo[4.3.0]nonan-5-ols (3a) and (3b) (or (8R,9S,10R)-9-methyl-1-azatricycro[8.3.0^1,10.0^3,8]tridecane-9-ol-3,6-diene (4b)) in 66% and 49% (or 31%) yields, respectively.