(3+2)-Cycloaddition of bicyclobutanes and thioketones: access to 2-thiabicyclo[2.1.1]hexanes without the use of catalysts or light

Abstract

A novel approach to the synthesis of the 2-thiabicyclo[2.1.1]hexane scaffold has been described. The method utilizes two highly reactive species: bicycle[1.1.0]butanes (BCBs) and thioketones. Their high reactivity enabled the formation of the desired product to occur under ambient conditions, without the need for catalysts, additives or light irradiation. To the best of our knowledge, this is the first rational synthesis of this specific skeleton. A variety of carbonyl-substituted BCBs, either with or without substituent at the other bridgehead, and thioketones were examined.