Enantioselective synthesis of 2-(2-arylcyclopropyl)glycines: Conformationally restricted homophenylalanine analogs


Demir A., Sesenoglu O., Ulku D., Arici C.

HELVETICA CHIMICA ACTA, vol.87, no.1, pp.106-119, 2004 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 87 Issue: 1
  • Publication Date: 2004
  • Doi Number: 10.1002/hlca.200490000
  • Title of Journal : HELVETICA CHIMICA ACTA
  • Page Numbers: pp.106-119

Abstract

Starting from simple aromatic aldehydes and acetylfuran, (E)-1-(furan-2-yl)-3-arylprop-2-en-1-ones (2) were synthesized in high yields. Cyclopropanation of the C=C bond with trimethylsulfoxonium iodide (Me3SO+I-) furnished (furan-2-yl)(2-arylcyclopropyl)methanones 3 in 90-97% yields. Selective conversion of cyclopropyl ketones to their (E)- and (Z)-oxime ethers 5 and oxazaborolidine-catalyzed stercoselective reduction of the C-N bond followed by separation of the formed diastereoisomers, furnished (2-arylcyclopropyl)(furan-2-yl)methanamines 6 in optically pure form and high yield. Oxidation of the furan ring of (S,S,S)-, (S,R,R)-, (R,S,S)-, and (R,R,R)-6a afforded the four stereoisomers of alpha-(2-phenylcyclopropyl) glycine (1a).