title: The photo-Nazarov reaction: scope and application.
abstract: The reaction conditions and scope of the photo-Nazarov reaction of aryl vinyl ketones were investigated. In contrast to the conventional acid-catalyzed methods, this photolytic electrocyclization proceeds in the neutral or basic conditions. Irradiating substrates bearing various aromatic rings, acid-sensitive groups, cyclohexenyl, cycloheptenyl, and unsaturated pyran with UV-light (254 nm) smoothly yielded hexahydrofluorenones and related structures. This photo-Nazarov reaction could also be applicable to the substrates carrying β-alkyl groups on the enone, which gave corresponding polycyclic rings containing quaternary centers. These photo-electrocyclized products may prove useful for synthesizing a variety of natural products and their derivatives. Further application of this mild photo-Nazarov reaction in the synthesis of taiwaniaquinol B was achieved.
authors.affiliation: Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University, 3663N Zhongshan Road, Shanghai 200062 (P.R. China), Fax: (+86) 21-62604784.
authors.forename: Shujun
authors.initials: S
authors.lastname: Cai
authors.forename: Zheming
authors.initials: Z
authors.lastname: Xiao
authors.forename: Yingbo
authors.initials: Y
authors.lastname: Shi
authors.forename: Shuanhu
authors.initials: S
authors.lastname: Gao
keywords: cyclization; electrocyclic reactions; ketones; natural products; photochemistry; synthetic methods