[reaction: see text] Treatment of bis-acetylenic amides or esters 3 with (eta(2)-propene)Ti(O-i-Pr)(2) generates functionalized titanacyclopentadienes which, upon hydrolytic workup, give exo, exo-cyclic conjugated dienes 4 in good yields. Some regio- and stereochemical aspects of their Diels-Alder reaction with dienophiles are also disclosed.
A facile preparation of exo-cyclic conjugated dienes fused to lactams or lactones via intramolecular coupling of acetylenes and their behavior in Diels-Alder reactions.
Department of Biomolecular Engineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
