Sv. Sergeev et al., NEW MOLECULAR REARRANGEMENT OF TRICYCLIC SPIROFURANOID INTO THE ALPHA,ALPHA-DISUBSTITUTED P-SEMIQUINOID SYSTEM, Russian chemical bulletin, 45(6), 1996, pp. 1499-1501
A new acid-catalyzed molecular rearrangement of Z-2,3,4,5,6,7-hexahydr
o-3-methoxy-carbonyl-4 hylspiro[benzofuran-2,1'-[2,5]cyclohexadien]-4-
one into nyl)(methoxycarbonyl)methylene]-2,5-cyclohexadiene was found.
The structure of the latter compound was confirmed analytically, by s
pectral data, and by X-ray diffraction study.