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

Org Biomol Chem. 2007 May 7;5(9):1405-15. doi: 10.1039/b701226h. Epub 2007 Mar 23.

Abstract

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

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Esters / chemistry
  • Lithium / chemistry
  • Oxazolidinones / chemistry
  • Piperidines / chemistry
  • Piperidones / chemical synthesis*
  • Piperidones / chemistry*
  • Stereoisomerism
  • Temperature

Substances

  • Esters
  • Oxazolidinones
  • Piperidines
  • Piperidones
  • Lithium