98126-82-0Relevant articles and documents
Furans in Synthesis. 5. Furan-Terminated Cationic Cyclizations in the Preparation of Fused, Spirocyclic and Bridged Ring Systems. An Application to the Synthesis of Nakafuran 9
Tanis, Steven P.,Herrinton, Paul M.
, p. 3988 - 3996 (2007/10/02)
The title compounds 36-42 and nakafuran 9 (43) were prepared by furan-terminated cationic cyclizations.The cyclization substrates, allylic alcohols 16, 17, 25, 26, 33, and 34, and the derived enone 19 were prepared by CuCN moderated SN2' addition of Grignard reagents derived from 2-(3-furyl)-1-bromoethane (12) and 3-(3-furyl)-1-bromopropane (13) to vinyl epoxides 14 and 22 and epoxy enol ether 21.Treatment of substrate allylic alcohols with a two-phase mixture of HCO2H and cyclohexane resulted in facile cyclization when the forming ring was six or seven membered.Enone closures proceeded only when a six-membered ring was produced or in the case of enone 48 which leads to nakafuran 9 (43).
