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

The C2-symmetric amino diol, (1R,5R)-3-aza-3-benzyl-1,5-diphenyl pentan-1, 5-diol, 1 [(R,R)-1] reacts with LiAlH4 to give the heterobimetallic complex 2 of the composition [(12-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.