Gold and platinum catalyzed cascade reaction of propargyl acetates bearing terminal alkynes or methyl ketones
作者:Taichi Kusakabe、Keisuke Kato
DOI:10.1016/j.tet.2010.12.010
日期:2011.2
A gold (III)-catalyzed cascade reaction of propargyl acetates bearing an extra terminal alkyne (1) afforded γ-keto esters 3 and lactones 4. These products should be generated through allenyl ketone intermediate B via a 1,2-acyloxy cyclization/fragmentation/cycloisomerization/hydrolysis sequence. On the other hand, the cascade reaction of α-acetoxy ketones bearing terminal alkynes 5 afforded lactone
The carbonylative cyclization of 1,1-diethynyl acetates mediated by Phbox/Pd(TFA)2 afforded a functionalized 4-cyclopentene-1,3-dione as a major product. In the absence of box ligand, a methoxycarbonylated orthoester was obtained predominantly.