Asymmetric Diels–Aider reactions of TMHD-acrylate using TiCl4·(ArnHg)mcomplexed Lewis acids

Abstract
Diels–Alder reaction of (3R, 5S)-5-benzoyloxy-2,2,6,6-tetramethyl-3-heptyl acrylate (TMHD-acrylate)1 with cyclopentadiene in the presence of TiCl4·(ArnHg)m complexed Lewis acids gives (1R,4R,6R)-2-norbornene-6-carboxylate derivative 4 predominantly, whereas the reaction in the presence of TiCl4 alone affords its enantiomer 2 preferentially.