Catalyst-free [2 + 1] annulations of conjugated dienes and sulfur Ylides: Synthesis of cyclopropane derivatives

Abstract

In this work, we report the [2 + 1] cycloaddition reaction between electron-deficient conjugated dienes and sulfur ylides under catalyst-free and base-free conditions. The method provides an efficient pathway for constructing cyclopropane frameworks. This protocol exhibits excellent regioselectivity, good yields, and broad functional group tolerance. Furthermore, the potential applications of this approach are demonstrated through gram-scale reactions and further synthetic transformations.