Synlett 2011(19): 2849-2851  
DOI: 10.1055/s-0031-1289537
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

C-Quaternary Vinylglycinols by Metal-Catalyzed Cyclization of Allylic Bistrichloroacetimidates

Kristine Klimovica, Liene Grigorjeva, Ansis Maleckis, Juris Popelis, Aigars Jirgensons*Latvian Institute of Organic Synthesis, Riga, 1006, Latvia
Fax: +3717541408; e-Mail: aigars@osi.lv;
Further Information

Publication History

Received 2 August 2011
Publication Date:
19 October 2011 (eFirst)

Abstract

Bistrichloroacetimidates derived from 2-substituted but-2-ene-1,4-diols are transformed into 4-substituted 4-vinyloxazolines in high yields and excellent regioselectivities when Lewis acids AlCl3, FeCl3, TMSOTf, BF3˙OEt2, and AgBF4 are used as catalysts as well as with the Pd(PPh3)2Cl2/AgBF4 catalytic system. Lower regioselectivity is achieved with a neutral PdCl2(MeCN)2 catalyst and this could be a consequence of a switch to a competitive but less selective reaction mechanism. It is demonstrated that 4-substituted 4-vinyloxazolines can be efficiently transformed to N-Boc-protected C -quaternary vinylglycinols in a one-pot procedure.