For the first time, asymmetric 1,4-addition of various malonates to enones has been carried out using tetrabutylammoniumtetrahydroborate (TBATB) in the presence of a chiral ligand. The Michael adducts were formed in reasonably good yields (61-67%) with moderate ee's at 0°C. 11B NMR spectroscopic studies explain this unexpected reactivity through the predominant formation of an aminodiol modified borate complex in the presence of a hydride acceptor. © 2005 Elsevier Ltd. All rights reserved.

Susan Abraham

Govindarajan Sundararajan

Boric acid

ligand

Malonic acid

TETRABUTYLAMMONIUMTETRAHYDROBORATE

TETRAHYDROBORATE

unclassified drug

article

chirality

complex formation

Michael addition

Nuclear magnetic resonance spectroscopy

priority journal

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Tetrahedron

(R, R)-(+)-2-[Benzyl-(2-hydroxy-2-phenylethyl)amino]-1-phenylethanol 1 is used as a chiral ligand in the synthesis of an optically active lanthanum-sodium amino diol complex LS-1. This heterobimetallic catalyst is quite effective as an asymmetric catalyst for various Michael addition reactions, 1H NMR study indicates the co-ordination of enone to the central lanthanum atom in LS-1. The reaction conditions were optimized and the adducts were obtained in high yield with moderate to high enantiomeric excess under extremely mild conditions. © 2002 Elsevier Science Ltd. All rights reserved.

Tetrahedron Asymmetry

Asymmetric Michael addition reactions using a chiral La-Na aminodiolate catalyst

Polyhedron

11B NMR study on the interaction of boric acid with Azomethine H

11B NMR investigation of the complexation behavior of borate with polysaccharides in aqueous solution

Organic Letters

Mechanistic Studies on Selectivity in the B(C6F5)3-Catalyzed Allylstannation of Aldehydes: Is Hypercoordination at Boron Responsible?

Journal of the American Chemical Society

The First Heterobimetallic Multifunctional Asymmetric Catalyst

Investigation of the active species in a Michael addition promoted by chirally modified tetrahydroborate

Journal	Tetrahedron
ISSN	00404020
Open Access	No