[3+2] Cycloaddition of Vinyl Cyclopropane and Hydroxylamines via Isocynate Intermediate to γ-Lactams

A general and efficient strategy for the synthesis of ?-lactams has been reported. The hydroxylamines form Lossen rearrangement products of electron-deficient group migration with base and then undergo [3+2] cycloaddition reaction with vinyl cyclopropane, which could be performed with broad substrate scope, excellent functional group tolerance and high efficiency to produce the desired products. It also allowed further modification to other derivatives of these ?-lactams.

Automated summary

A general and efficient approach for the synthesis of ?-lactams has been developed. Hydroxylamines undergo Lossen rearrangement with base, followed by [3+2] cycloaddition reaction with vinyl cyclopropane, leading to the formation of desired products. This strategy exhibits broad substrate scope, excellent functional group tolerance, and high efficiency, allowing for further modifications of the resulting ?-lactams derivatives.