In the searching for zwitterionic intermediates on reaction paths of [3 + 2] cycloaddition reactions between 2,2,4,4-tetramethyl-3-thiocyclobutanone S-methylide and polymerizable olefins

Abstract

DFT calculations show that the [3 + 2]-cycloaddition of 2,2,4,4-tetramethyl-3-thiocyclobutanone <italic>S</italic>-methylide with nitroethene takes place according to a polar, two-step mechanism with a zwitterionic intermediate.