Reaction of 1,2-dihydrobenzocyclobutene-1-carbonitriles with methyl acrylate as an unsymmetric dienophile

Abstract

Thermolysis of the 1,2-dihydrobenzocyclobutene-1-carbonitriles (11) and (12) in the presence of methyl acrylate gives in each case two stereoisomeric 1-cyano-2-methoxycarbonyltetralins [(16) and (17), and (18) and (19), respectively]. The cis-isomer (19) was converted into the more stable trans-isomer (17) by treatment with sodium hydride.