Unusual mechanism of hydrolysis of the tosyl cyanide–cyclopentadiene adduct to the lactam 2-azabicyclo[2.2.1]hept-5-en-3-one

Abstract

Hydrolysis of the cycloaddition product derived from tosyl cyanide and cyclopentadiene was investigated using ¹⁸O label incorporation experiments; thus, sulfonyl imine 2 was transformed into ¹⁸O labelled lactam 3 with ¹⁸O labelled acetic acid, which is consistent with the intervention of intermediate 6 during the hydrolysis.