Highly regioselective tandem formal substitution and decarboxylation of 2-acyl-1-chlorocyclopropanecarboxylates with sodium sulfinates

This article reported a highly regioselective tandem formal nucleophilic substitution and decarboxylation reaction of alkyl 2-acyl-1-chlorocyclopropanecarboxylates with sodium sulfinates under basic conditions. Actually, alkyl 2-acyl-1-chlorocyclopropanecarboxylates could be easily converted into cyclopropene intermediates by simple 1,2-elimination of hydrogen chloride, and this highly reactive cyclopropene quickly combines with sodium sulfinate via a regioselective 1,4-Michael addition. Subsequent esterolysis and decarboxylation of the 1,4-Michael adducts afforded 1-aroylsulfonyl-2-aroylcyclopropanes in high yields. This observation firstly demonstrates that direct Michael addition of sodium sulfinates with reactive cyclopropene is really workable.