Sequential Synthesis of Furans from Alkynes: Successive Ruthenium(II)- and Copper(II)-Catalyzed Processes

(Chemical Equation Presented) Step in time: 2,5-Disubstituted furans can be prepared from terminal alkynes in one pot using two successive catalytic reactions (see scheme; p-TSA=para-toluene-sulfonic 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. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.