The reaction between bis(trimethylsilyl)cyclopentadiene and dichloroketen, and the Diels–Alder reactions between N-phenylmaleimide and two silylated methylcyclopentadienes

Abstract

Bis(trimethylsilyl)cyclopentadiene reacts with dichloroketen to give only the adduct (7) derived from the 2,5-disilylated isomer (5). Methyl(trimethylsilyl)cyclopentadiene (18) and trimethylsilylmethylcyclopentadiene (21) give Diels–Alder adducts (19) and (20) and (22) and (23) in which the regioselectivity is unaffected by the presence of the silyl group. Epoxidation of the adduct (22) and acid-catalysed opening of the epoxide lead to formation of the exo-methylenenorbornane (26) in a rearrangement controlled by the presence of the silyl group.