General Cyclopropane Assembly by Enantioselective Transfer of a Redox‐Active Carbene to Aliphatic Olefins

Going to the source: The asymmetric synthesis of cyclopropanes is currently designed using specific strategies that depend on the materials available and the final functionality of each target. Presented here is a comprehensive approach that engages simple feedstocks, including aliphatic olefins, with a single redox‐active carbene precursor (NHPI‐DA), which acts as a universal source for a chiral C−H unit.

Abstract

Asymmetric cyclopropane synthesis currently requires bespoke strategies, methods, substrates, and reagents, even when targeting similar compounds. This approach slows down discovery and limits available chemical space. Introduced herein is a practical and versatile diazocompound and its performance in the first unified asymmetric synthesis of functionalized cyclopropanes. The redox‐active leaving group in this reagent enhances the reactivity and selectivity of geminal carbene transfer. This effect allowed the asymmetric cyclopropanation of various olefins, including unfunctionalized aliphatic alkenes, that enables the three‐step total synthesis of (−)‐dictyopterene A. This unified synthetic approach delivers high enantioselectivities that are independent of the stereoelectronic properties of the functional groups transferred. Our results demonstrate that orthogonally differentiated diazocompounds are viable and advantageous equivalents of single‐carbon chirons.

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