Synthesis 2010(21): 3663-3669  
DOI: 10.1055/s-0030-1258213
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Yb(OTf)3-Promoted ZnCl2-Catalyzed Conia-Ene Reaction of Linear β-Alkynic β-Dicarbonyls

Yu Liu, Ren-Jie Song, Jin-Heng Li*
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education), Hunan Normal University, Changsha 410081, P. R. of China
Fax: +86(731)88872101; e-Mail: jhli@hunnu.edu.cn;
Further Information

Publication History

Received 25 June 2010
Publication Date:
13 August 2010 (online)

Abstract

An atom-economical and solvent-free ytterbium(III) triflate promoted, zinc(II) chloride catalyzed Conia-ene method has been developed for the construction of five- to six-membered-ring carbocycles. In the presence of zinc(II) chloride and ytterbium(III) triflate, a variety of linear β-alkynic β-keto esters and β-alkynic β-diketones were cyclized under neat conditions in moderate to good yields. It is noteworthy that the selectivity toward five- or six-membered­-ring carbocycles depends on substituents at the terminal alkynes.