Atropisomeric chiral dienes in asymmetric catalysis: C(2) -symmetric (Z,Z)-2,3-bis[1-(diphenylphosphinyl)ethylidene]tetralin as a highly active Lewis base organocatalyst

Abstract

Diene catalysts with a twist: The title C2 -symmetric tetralin-fused 1,3-butadiene derivative is atropisomeric and can be resolved into the two helical enantiomers. The optically pure compound showed excellent enantioselectivity as well as unusually high catalytic activity as a chiral Lewis basic organocatalyst in the asymmetric allylation of various aldehydes with β-substituted allyltrichlorosilanes.

Keywords: Lewis bases; allylation; asymmetric synthesis; atropisomerism; dienes.