1,2-Thiazines and related heterocycles. Part 1. An investigation of the cycloadditions of N-sulphinylanilines with 1,4-epoxy-1,4-dihydronaphthalene and other alkenes

Abstract

Evidence is adduced from the character of the alkenes which cycloadd to N-sulphinylanilines and from a kinetic investigation of the reactions of N-sulphinylanilines with 1,4-epoxy-1,4-dihydronaphthalene, examining the effects upon reaction rate of solvent polarity, temperature, and substitution in the N-sulphinylanilines, that the cycloadditions are pericyclic reactions of Diels–Alder type with inverse electron demand. A degree of charge separation in the transition state is indicated but this is small and confined essentially to the sulphinylaniline moiety.