Organic Letters 2008-10-02

Simple chiral diene ligands provide high enantioselectivities in transition-metal-catalyzed conjugate addition reactions.

Kazuhiro Okamoto, Tamio Hayashi, Viresh H Rawal

Index: Org. Lett. 10 , 4387-4389, (2008)

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Abstract

Chiral dienes possessing the bicyclo[2.2.2]octadiene framework were prepared readily through the [4 + 2] cycloaddition of ( R)-alpha-phellandrene with methyl propiolate as the key step. Diene 9, substituted with a tertiary alcohol on one of the two double bonds, is prepared in just one step from the cycloadduct and is highly effective as a chiral ligand for rhodium-catalyzed asymmetric conjugate addition reactions, giving the corresponding addition products with higher enantioselectivity than other chiral dienes.