An Effective Bifunctional Thiourea Catalyst for Highly Enantio- and Diastereoselective Michael Addition of Cyclohexanone to Nitroolefins

Abstract

A series of new tunable and bifunctional thiourea catalysts have been synthesized and their catalytic activities are evaluated in the direct Michael addition of cyclohexanone to nitroolefins. High isolated yields (up to 97%), enantioselectivities (up to 98%) and diastereoselectivities (up to 99:1) were obtained under the optimal conditions.

Key words

Asymmetric catalysis - Michael addition - bifunctional thiourea catalyst - organocatalysis - nitroolefins

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8

The reaction proceeded slowly, and there were only trace amounts of products formed even after seven days.