title: Tunable arylative cyclization of 1,6-enynes triggered by rhodium(III)-catalyzed C-H activation.
abstract: Two tunable arylative cyclizations of cyclohexadienone-containing 1,6-enynes are reported via rhodium(III)-catalyzed C-H activation of O-substituted N-hydroxybenzamides. The use of different O substituents, i.e. O-Piv and O-Me, on the directing group allows the formation of either tetracyclic isoquinolones through an Ⓝ-Michael addition process or hydrobenzofurans through a Ⓒ-Michael addition process. Mechanistic investigations of these two cascade reactions clearly indicated that the C-H bond cleavage process was involved in the turnover-limiting step. Furthermore, the cyclization products could be subjected to various transformations for elaborating the pharmaceutically and synthetically valuable potential. This is the first example of a rhodium(III)-catalyzed arylative cyclization reaction of 1,6-enynes, and the results extend the application realm of Cp*Rh(III)-catalyzed C-H activation cascade reactions.
authors.affiliation: CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, People's Republic of China.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Fukui
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Zhi-Tao
authors.initials: ZT
authors.lastname: He
authors.forename: Nuo-Yi
authors.initials: NY
authors.lastname: Wu
authors.forename: Ping
authors.initials: P
authors.lastname: Tian
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Lin