Cycloadditions to conjugated diallenes

Abstract

Conjugated diallenes of the general structure (1) reacted with N-phenyl-1,2,4-triazoline-3,5-dione (5) to give [4 + 2] cycloaddition products; the meso-diallene (4) with (5) gave the unsymmetrical Diels–Alder adduct (8) and the ‘ene’ product (9). Reaction of diallene (2) with sulphinylaniline gave the Diels–Alder product (11) while reactions with ketens resulted in both [2 + 2] and [4 + 2] cycloaddition products.