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

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.

Synthesis of Carbamoyl Azides from Redox-Active Esters and TMSN3

“…Unexpectedly, instead of forming the carbamoyl azide 2a , benzoyl azide turned out to be the major product when acetone was utilized as the solvent (entry 13). 13 Notably, when the reaction was run at a lower temperature, almost no 2a formed, presumably because of the blocked transformation of benzoyl azide into 2a . In addition, a high reaction temperature resulted in a messy reaction (entries 14–16).…”