Steric Hindrance Facilitated Synthesis of Enynes and Their Intramolecular [4 + 2] Cycloaddition with Alkynes
作者:Juan J. González、Andrés Francesch、Diego J. Cárdenas、Antonio M. Echavarren
DOI:10.1021/jo9717853
日期:1998.5.1
The palladium-catalyzed insertion of 1-alkynes into internal alkynes which are bent out of linearity by the interference with a peri or ortho substituent led to enynes regioselectively. The resulting enynes undergo a new type of intramolecular thermal cycloaddition, which can be used for the annulation of an aryl ring onto naphthalene derivatives to afford fluranthenes. The cyclization of (E)-1-(1-buten-3-ynyl)-8-ethynylnaphthalene could also be performed in the presence of a Cu(I) catalyst at room temperature.