Phenanthroline-Initiated Anti-selective Hydrosulfonylation of Unactivated Alkynes with Sulfonyl Chlorides

Abstract

A simple and general method for anti-selective hydrosulfonylation of unactivated alkynes with sulfonyl chlorides in the presence of a catalytic amount of phenanthroline-based Lewis base and (Me3Si)3SiH as the hydrogen atom donor has been developed. The protocol proceeds efficiently under mild and metal-free conditions, delivering a diverse set of (Z)-vinyl sulfones with high stereoselectivity. Additionally, the method displays excellent functional-group compatibility and can be applied to the late-stage modifications of complex drugs and their derivatives. Experimental and density functional theory studies unveiled that the key to the transformation’s success is the employment of a phenanthroline-based Lewis base, which interacts with sulfonyl chlorides to form a halogen-bond complex that accelerates the cleavage of the S–Cl bonds of sulfonyl chlorides under the irradiation of visible light.