title: Direct synthesis of highly substituted 2-cyclohexenones and sterically hindered benzophenones based on a [5C + 1C] annulation.
abstract: The regiospecific [5C + 1C] annulation of readily available alpha-alkenoyl ketene (S,S)-acetals 1 with aryl methyl ketones 2, the less active methylene compounds, has been developed. Upon treatment of 1 with 2 in the presence of t-BuOK in DMF at room temperature, highly substituted 2-cyclohexenones 3 were synthesized in high to excellent diastereoselectivities with high yields. On the basis of this strategy, sterically hindered benzophenones 4 were conveniently prepared via the iodonation-aromatization of 2-cyclohexenones 3 with I(2) in MeONa/MeOH basic medium. Furthermore, benzophenones 4 were also obtained directly from 1 and 2 following a sequential [5 + 1] annulation-iodonation-aromatization procedure in a one-pot operation.
authors.affiliation: Department of Chemistry, Northeast Normal University, Changchun 130024, China.
authors.forename: Zhenqian
authors.initials: Z
authors.lastname: Fu
authors.forename: Mang
authors.initials: M
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Dong
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Qun
authors.initials: Q
authors.lastname: Liu