Distortion/interaction analysis of the reactivities and selectivities of halo- and methoxy-substituted carbenes with alkenes

Abstract

The transition structures for the (2+1) cycloadditions of dichlorocarbene, chlorofluorocarbene, and difluorocarbene to cyclohexene, 1-hexene, ethylene, and a-chloroacrylonitrile were located using quantum mechanical methods (M06-2X). In addition, transition structures for the (2+1) cycloadditions of chloromethoxycarbene, fluoromethoxycarbene, and dimethoxycarbene to ethylene and α-chloroacrylonitrile were computed. Except for the reactions with ethylene, these cycloadditions were studied experimentally and computationally by Moss and Krogh-Jespersen (Zhang, M.; Moss, R. A.; Thompson, J.; Krogh-Jespersen, K. J. Org. Chem. 2012, 77, 843-850). As a complement to the work of those groups, we have utilized the distortion/interaction model to understand reactivities and selectivities. Gas-phase calculations were carried out at the M06-2X/6-31+G(d,p) level of theory.