DDQ-MEDIATED FORMATION OF CARBON-CARBON BONDS - OXIDATION OF IMINES

The reaction of imines with alkynes and alkenes, in the presence of 2, 3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), to give quinoline derivat ives is described. The mechanism of the annulation is discussed, and e vidence supporting a non-concerted pathway, at least when the alkene i s butyl vinyl ether, is reported. Preliminary information is also give n about solid adducts of imines with DDQ, which do not seem to be invo lved in the reaction path leading to quinolines, and should account fo r the dependence of product yields on the position of substituents on the starting imines.