Stereoselective synthesis of nipecotic acid derivatives via palladium-catalyzed decarboxylative cyclization of gamma-methylidene-delta-valerolactones with imines.

Ryo Shintani, Masataka Murakami, Tamio Hayashi

Index: Org. Lett. 11(2) , 457-9, (2009)

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Abstract

A new synthetic method of multisubstituted nipecotic acid (piperidine-3-carboxylic acid) derivatives has been developed by way of palladium-catalyzed decarboxylative cyclization of gamma-methylidene-delta-valerolactones with imines. By employing the diethoxyphosphinoyl group as the N-protecting group for imines, the reaction proceeds smoothly with high diastereoselectivity. The products thus obtained can be further derivatized with high efficiency under simple reaction conditions.