Ruthenium-Catalyzed [2+2] Cycloadditions of Alkynyl Sulfides and Alkynyl Sulfones
作者:Nicole Riddell、William Tam
DOI:10.1021/jo052295a
日期:2006.3.1
Ruthenium-catalyzed [2+2] cycloadditions of bicyclicalkenes with alkynyl sulfides and alkynyl sulfones were investigated. The sulfide and sulfone moieties were found to be compatible with the Ru-catalyzed cycloadditions, giving the corresponding cyclobutene cycloadducts in good yields. The sulfonyl-containing cycloadducts can be transformed into a variety of products that are difficult to obtain via
[GRAPHICS]A new methodology for the synthesis of substituted alkynes is described. In the presence of copper(I) thiophene 2-carboxylate (CuTC) or copper (I) 3-methylsalicylate (CuMeSal), the palladium-catalyzed cross-coupling of thioalkyne derivatives with boronic acids affords functionalized alkynes in yields ranging from 39 to 91%. This coupling occurs efficiently under mild, nonbasic conditions with a wide variety of thioalkynes and boronic acids, providing a reaction complementary to the Sonogashira protocol.