A synthesis of conjugated dienes from aromatic, five-membered heterocycles
作者:Ernest Wenkert、Michael H. Leftin、Enrique L. Michelotti
DOI:10.1039/c39840000617
日期:——
Reaction of furan, thiophene, selenophene, and tellurophene as well as 2-methyl and 2,5-dimethyl derivatives of the first two heterocycles with phenyl-, methyl-, and n-butyl-magnesium bromides in the presence of ligated nickel dichloride are shown to yield buta-1,3-dienes mostly with retention of configuration.
addition of alkylcopper compounds to 1-alkynes, are transformed with retention to various ethylenic structures; 1-deutero-1-alkenes, symmetrical conjugated dienes, 1-iodo-1-alkenes, di- or tri-substituted alkenes and primary or secondary allylic alcohols.
and have been shown to be capable of heterolysis of molecular hydrogen, a property that has led to their use in hydrogenation reactions of polarized multiple bonds. Here, we describe a general approach to the hydrogenation of alkynes to cis-alkenes under mild conditions using the unique ansa-aminohydroborane as a catalyst. Our approach combines several reactions as the elementary steps of the catalytic