Photochemistry of Phenylallenes in Protic Media. Formation of Allyl Cations by Way of Vinylcarbenes ... Fakultat fir Chemie, Ruhr-Universitat Bochum 0-44780 Bochum, Germany ... Max-Planck-Institut fir Strahlenchemie 0-45413 Mulheim, Germany Received February 24, 1995 ... Considerable effort has been directed toward elucidating the photochemistry of allenes (propadienes).' The photoisomer- ization of allene to cyclopropene and propyne was fist ...