Stereoretentive O-to-C rearrangement of vinyl acetals: solvent cage effects as a stereocontrol element

J Am Chem Soc. 2002 Aug 21;124(33):9720-1. doi: 10.1021/ja026972j.

Abstract

The Lewis acid-mediated rearrangement of chiral vinyl acetals may be induced to provide the product of stereoretention using Me3Al and BF3.OEt2 in concert. The selectivities obtained in this reaction (86:14 to 96:4) are complementary to that observed when relying on oxocarbenium facial bias to control the newly formed stereocenter. Evidence is presented that this reaction occurs by tight ion-pair binding in the solvent cage. The relay of C-O bond stereochemistry to a C-C bond stereocenter via ionic intermediates is an addition to similar established methods such as the Claisen rearrangement.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetals / chemistry*
  • Ethers, Cyclic / chemistry
  • Solvents / chemistry
  • Stereoisomerism
  • Vinyl Compounds / chemistry*

Substances

  • Acetals
  • Ethers, Cyclic
  • Solvents
  • Vinyl Compounds