title: PtI2-catalyzed cyclization of 3-acyloxy-1,5-enynes with the elimination of HOAc and a benzyl shift: synthesis of unsymmetrical m-terphenyls.
abstract: A novel cyclization of 3-acyloxy-1,5-enynes is developed in the presence of PtI2 for the synthesis of substituted unsymmetrical m-terphenyls in good to excellent yields. Two unique steps are involved in this transformation, which includes the elimination of HOAc and benzyl group migration. DFT calculations indicated that the rate-determining step is the migration of the benzylic carbocation to form a zwitterionic intermediate followed by the elimination of HOAc. The subsequent cyclopropanation of the zwitterionic intermediate is the regioselectivity-determining step.
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, the College of Chemistry, Nankai University, Weijin Road 94#, Nankai District, Tianjin 300071, China.
authors.forename: Kaimeng
authors.initials: K
authors.lastname: Huang
authors.forename: Xiaona
authors.initials: X
authors.lastname: Ke
authors.forename: Hongkai
authors.initials: H
authors.lastname: Wang
authors.forename: Junying
authors.initials: J
authors.lastname: Wang
authors.forename: Chenchen
authors.initials: C
authors.lastname: Zhou
authors.forename: Xiufang
authors.initials: X
authors.lastname: Xu
authors.forename: Lingyan
authors.initials: L
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Li