Reactions of alkylidenephosphoranes with symmetrically substituted p-quinones

Article abstract of DOI:10.1016/S0040-4020(97)00905-8

The reaction of p-quinone 1 with ylides 2a and 2b afforded the corresponding phosphonium salts 8a,b, p-quinone-dimethanides 4a,b(Z) and 5a,b(E); substituted phenols 7a,b(Z and E) and coumarin-derivative 11 (only with 2a). The reaction of 1 with ylide 2c gave, besides 4c, 5c and 8c, hydroquinone[1]cyclobutene 16 and the Diels-Alder product 17. Reactions of 1 with 2d and 3 (salts) in the presence of sodium alkoxide yielded through preferred attack on the nitrile function, azo-22 and bisimino-24 compounds, respectively.