Synthesis of Methylenebicyclo[3.2.1]octanol by a Sm(II)-Induced 1,2-Rearrangement Reaction with Ring Expansion of Methylenebicyclo[4.2.0]octanone
journal contributionposted on 29.06.2017, 14:35 by Kazuhiko Takatori, Shoya Ota, Kenta Tendo, Kazuma Matsunaga, Kokoro Nagasawa, Shinya Watanabe, Atsushi Kishida, Hiroshi Kogen, Hiroto Nagaoka
Direct conversion of methylenebicyclo[4.2.0]octanone to methylenebicyclo[3.2.1]octanol by a Sm(II)-induced 1,2-rearrangement with ring expansion of the methylenecyclobutane is described. Three conditions were optimized to allow the adaptation of this approach to various substrates. A rearrangement mechanism is proposed involving the generation of a ketyl radical and cyclopentanation by ketyl–olefin cyclization, followed by radical fragmentation and subsequent protonation.