The unusual reaction of tetrachlorothiophene dioxide with an adduct of 5,6-bismethylenenorbornene and hexachloronorbornadiene
Abstract
Hexachloronorbornadiene forms a 1 : 1 adduct 3 with 5,6-bismethylenenorbornene, which, on reaction with 1,2,3,4-tetrachlorothiophene dioxide, yields by loss of SO2, cycloreversion and further cycloaddition two compounds shown by mass, 13C NMR and 1H NMR spectroscopy and a single-crystal X-ray structure determination to be the isomeric products of a rare type of specific diene-capture by perchlorothiophene dioxide; a rational explanation for this and other examples is proposed, and a further example of norbornene sp2C pyramidalisation is disclosed.