(Thiolan-2-yl)diphenylmethanol Benzyl Ether-Catalyzed Asymmetric Cyclopropanation of Chalcones.

We devised a new method for asymmetric cyclopropanation by employing ( S )-(thiolan-2-yl)diphenylmethanol benzyl ether as an organocatalyst. Under optimal conditions, an in situ generated sulfur ylide reacts with ( E )-chalcones via a Johnson-Corey-Chaykovsky reaction to afford a variety of cyclopropanes in excellent yields and stereoselectivities. This strategy employs low-environmental-risk reaction conditions and reusable catalysts. Hence, it is a green and efficient method for constructing cyclopropane scaffolds.