Tetrahedron Letters

Photocyclization of a conjugated triaryl 'Y-enyne'

BR Kaafarani, DC Neckers

Index: Kaafarani, Bilal R.; Neckers, Douglas C. Tetrahedron Letters, 2001 , vol. 42, # 25 p. 4099 - 4102

Full Text: HTML

Citation Number: 28

Abstract

Upon irradiation at 350 nm, in the presence/absence of oxygen,'Y-enyne'1 undergoes electrocyclic ring closure to photoproduct 4. A mechanism involving an allene intermediate is proposed. In nonpolar solvents a [1, 5] H shift affords the photoproduct, while in methanol protonation of the central allenic carbon occurs. Quantum yields of the photoreaction in the different solvents were measured.