Synthesis of enantiomerically enriched allenes by (-)-sparteine-mediated lithiation of alkynyl carbamates

Org Lett. 2001 Apr 19;3(8):1221-4. doi: 10.1021/ol0157104.

Abstract

[reaction: see text]. The alpha-deprotonation of alkynyl carbamates 3 with the chiral base (-)-sparteine (4)/n-butyllithium, transmetalation with ClTi(O(i)()Pr)3, and subsequent substitution with an aldehyde results in the formation of enantioenriched 4-hydroxyallenyl carbamates 11. Stereoselection is determined by dynamic resolution of the lithium/(-)-sparteine complexes by selective crystallization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / chemistry*
  • Alkadienes / chemical synthesis*
  • Lithium / chemistry*
  • Models, Chemical
  • Models, Molecular
  • Sparteine / chemistry*

Substances

  • Aldehydes
  • Alkadienes
  • Sparteine
  • propadiene
  • Lithium