title: Catalytic asymmetric benzylic C-H activation by means of carbenoid-induced C-H insertions.
abstract: Tetrakis[N-[4-dodecylphenyl)sulfonyl]-(S)-prolinate]dirhodium [Rh(2)(S-DOSP)(4)]-catalyzed decomposition of methyl aryldiazoacetates in the presence of substituted ethylbenzenes results in benzylic C-H activation by means of a rhodium-carbenoid-induced C-H insertion. A Hammet study showed that positive charge buildup occurred on the benzylic carbon in the transition state of the C-H activation step. C-H activation of toluene and isopropylbenzene is possible, but a competing double cyclopropanation occurs with these substrates. The C-H activation is highly regioselective and enantioselective, and in certain cases, moderate diastereoselectivity is also possible.
authors.affiliation: Department of Chemistry, University at Buffalo, State University of New York, 14260-3000, USA. hdavies@acsu.buffalo.edu
authors.forename: Huw M L
authors.initials: HM
authors.lastname: Davies
authors.forename: Qihui
authors.initials: Q
authors.lastname: Jin
authors.forename: Pingda
authors.initials: P
authors.lastname: Ren
authors.forename: Andrey Yu
authors.initials: AY
authors.lastname: Kovalevsky