Lithium bis[(1 R,5 R)-3-aza-3-benzyl-1,5-diphenylpentan-1,5-diolato]-aluminium — A new heterobimetallic catalyst for Michael addition reactions

Abstract

The C 2-symmetric amino diol, (1 R,5 R)-3-aza-3-benzyl-1,5-diphenyl pentan-1, 5-diol, 1 [ (R,R)- 1 ] reacts with LiAlH 4 to give the heterobimetallic complex 2 of the composition [( 1 2-Al)Li]. Complex 2 was characterised by 1H-, 13C-, 27Al- and 7Li-NMR spectral data. Also, 2 when used in catalytic amounts accelerates Michael addition of malonates and thiophenol to α,β-unsaturated compounds like aldehydes, ketones, cyano and nitro compounds with high yield. Asymmetric induction in the Michael adducts has also been observed when a enantiomerically pure catalyst 2 was employed.