Issue 9, 2007

Asymmetric three- and [2 + 1]-component conjugate addition reactions for the stereoselective synthesis of polysubstituted piperidinones

Abstract

The efficiency and stereoselectivity of the conjugate addition of lithium (Z)- or (E)-β-amino ester enolates, generated by lithium amide conjugate addition to an α,β-unsaturated ester or deprotonation of a β-amino ester, respectively, to a range of α,β-unsaturated acceptors has been investigated. Deprotonation of a β-amino ester with LDA, followed by conjugate addition to a chiral α,β-unsaturated oxazolidinone gives high 2,3-anti selectivity (∼90% d.e.), with hydrogenolysis and purification to homogeneity generating stereodefined trisubstituted piperidinones as single stereoisomers. Asymmetric three-component couplings of α,β-unsaturated esters and alkylidene malonates initiated by lithium amide conjugate addition proceeds with high levels of 2,3-anti stereoselectivity, with hydrogenolysis giving tetrasubstituted piperidinones.

Graphical abstract: Asymmetric three- and [2 + 1]-component conjugate addition reactions for the stereoselective synthesis of polysubstituted piperidinones

Supplementary files

Additions and corrections

Article information

Article type
Paper
Submitted
26 Jan 2007
Accepted
27 Feb 2007
First published
23 Mar 2007

Org. Biomol. Chem., 2007,5, 1405-1415

Asymmetric three- and [2 + 1]-component conjugate addition reactions for the stereoselective synthesis of polysubstituted piperidinones

S. G. Davies, P. M. Roberts and A. D. Smith, Org. Biomol. Chem., 2007, 5, 1405 DOI: 10.1039/B701226H

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