Vicinal bis(trifluoroacetimidoyl chloride)s: novel building blocks for the synthesis of benzo-fused eight-membered rings via [2 + 2 + 2] cycloadditions

Vicinal bis(trifluoroacetimidoyl chloride)s, a novel kind of fluorinated building block, were obtained from o-phenylenediamines in the presence of TFA, triethylamine, triphenylphosphine and tetrachloromethane. Based on these blocks, a new synthesis involving [2 + 2 + 2] cycloaddition reactions for trifluoromethylated benzo-fused eight-membered rings was disclosed.