Electrooxidative Ring-Opening and Strain-Release-Driven Skeletal Rearrangement of Cyclopropenes

Abstract

We develop two distinct electrooxidative strategies for the ring-opening and strain-release-driven rearrangement of cyclopropenes when reacting with alcohols and trimethylsilyl azide, yielding gem-dialkoxyallylated compounds and tetrasubstituted alkenyl nitriles. The synthesis of allylated derivatives starts with the direct anodic oxidation of the cyclopropene ring to form a cyclopropene radical cation. This radical cation undergoes addition by an alkoxide (acting as a nucleophile) at the C2 position, followed by regioselective cleavage of the C1–C2 bond. For alkenyl nitriles, anodic oxidation of the radical precursor produces an azide radical that adds to the cyclopropene ring at the less-substituted C3 position. This leads to regioselective cleavage of the C1–C3 bond. Additionally, the postreaction modifications and the ability to synthesize deuterated allyl compounds further demonstrate the utility of these transformations.