Sequential Synthesis of Furans from Alkynes: Successive Ruthenium(II)- and Copper(II)-Catalyzed Processes
作者:Min Zhang、Huan-Feng Jiang、Helfried Neumann、Matthias Beller、Pierre H. Dixneuf
DOI:10.1002/anie.200805531
日期:——
5‐Disubstituted furans can be prepared from terminal alkynes in one pot using two successive catalytic reactions (see scheme; p‐TSA=para‐toluenesulfonic acid). First, a 1,3‐dienyl alkyl ether is produced by the dimerization of a terminal alkyne and addition of an alcohol catalyzed by [RuCp*(NCMe)3][PF6]. Then, consecutive hydrolysis and cyclization catalyzed by CuCl2 provides the 2,5‐disubstituted furan.