Chirality of exo-heterosubstituted semiquinoid systems

Conclusions The observation of diastereotopism of the methoxy groups (at a distance of eight bonds from the asymmetric center) in the PMR spectra of 4,4-disubstituted l-(dimethylphosphorylmethylidene)-2,5-cyclohexadienes has been used to demonstrate the chirality of para-semiquinoid systems containing a heteroatom in the unsaturated exo-fragment of the molecule and two substituents distinguishable from each other in the geminal position.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2296–2299, October, 1986.