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

The C-2-symmetric amino diol, (IR,5R)-3-aza-3-benzyl-1,5-diphenyl pentan-1, 5-diol, 1 [(R,R)-1] reacts with LiAlH4 to give the heterobimetallic comple x 2 of the composition [(II-AI)LI]. Complex 2 was characterised by H-1-, C- 13-, Al-27- and Li-7-NMR spectral data. Also, 2 when used in catalytic amou nts accelerates Michael addition of malonates and thiophenol to alpha,beta- unsaturated compounds like aldehydes, ketones, cyano and nitro compounds wi th high yield. Asymmetric induction in the Michael adducts has also been ob served when a enantiomerically pure catalyst 2 was employed. (C) 1999 Elsev ier Science Ltd. All rights reserved.