Novel fulvenes capto-datively substituted at C 6

A set of four fulvenes bearing both electron-withdrawing and -donating aryl groups at C 6 was prepared and shown to be fairly stable, except for the dimerisation of the anisyl-nitrophenyl-fulvene 1a, which also underwent a (4π + 2π) cycloaddition with C,N-diphenylnitrone.