[2 + 2] cycloadditions of 2,2-bis(trifluoromethyl)ethylene-1,1-dicarbonitrile with vinyl sulfides and ketene S,S-acetals
作者:Reinhard Brückner、Rolf Huisgen
DOI:10.1016/0040-4039(90)80125-6
日期:1990.1
In its [2+2] cycloadditions to vinyl sulfides, the title olefin (BTF) exceeds tetracyanoethylene up to 8200-fold in rate, but is more sensitive to steric hindrance by β-substituents in the donor olefin; some vinyl sulfides react faster than vinylethers with BTF. The dependence of rate on solvent polarity Is In harmony with zwitterionic Intermediates.