Lewis acid-catalysed cyclisations of 1-anthryl styryl ketone; benz[de]-anthracen-3-one

Abstract

Cyclisation of 1-anthryl styryl ketone with aluminium chloride gave a small yield of the unstable base benz[de]anthracen-3-one (1a), whereas cyclisation with polyphosphoric acid gave a mixture of 2,3-dihydro-3-phenylcyclopent[a]anthracen-1-one and a stable analogue of (1a), 1-phenylbenz[de]anthracen-3-one. Comparison is made with reactions of 9-anthryl styryl ketone and 1-naphthryl styryl ketone under similar conditions and it is concluded that 1-anthryl styryl ketone is not an intermediate in the disproportionation of 9-anthryl styryl ketone to anthracene and anthracene-9,10-diyl bis(styryl ketone).