Synlett 2008(7): 1081-1085  
DOI: 10.1055/s-2008-1072655
LETTER
© Georg Thieme Verlag Stuttgart · New York

New Cationic Bisoxazoline-Au(III) Complex Catalyzed Cycloisomerization of 1-Allenyl-1-ethynyl Acetate

Keisuke Kato*a, Takuya Kobayashia, Takeo Fujinamia, Satoshi Motodatea, Taichi Kusakabea, Tomoyuki Mochidab, Hiroyuki Akita*a
a Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
Fax: +81(474)721825; e-Mail: kkk@phar.toho-u.ac.jp;
b Department of Chemistry, Faculty of Science, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan
Further Information

Publication History

Received 17 January 2008
Publication Date:
28 March 2008 (online)

Abstract

Treatment of 1-allenyl-1-diethynyl acetates in the presence of a Au or Pt catalyst (5 mol%) in toluene at room temperature, followed by methanolysis, gave 4-methylene-2-cyclopentenones. The new cationic bisoxazoline (box)-Au(III) complex {(S,S)-Phbox- or [(R,R)-Bnbox AuCl2]SbF6} accelerated the reaction, providing the products in moderate yield (60-69%).