Total Synthesis of (.+-.)-Gleenol and (.+-.)-Axenol via a Functionalized Spiro[4.5]decane
作者:Atsuo Nakazaki、Tomohiro Era、Susumu Kobayashi
DOI:10.1248/cpb.55.1606
日期:——
was accomplished through a readily available spiro[4.5]decane. The key features of the synthesis of 1 and 2 include Claisen rearrangement to afford the multi-functionalized spiro[4.5]decane 4 as a single diastereomer in excellent yield, installation of the C7 isopropyl group via ketene dithioacetal instead of direct alkylation and a diastereoselective reduction of ketone under the Birch conditions.
Silicon guided rearrangement of epoxydecalines to spirocyclic compounds. Synthesis of gleenol and axenol from carvone
作者:Gonzalo Blay、Ana M. Collado、Begoña García、José R. Pedro
DOI:10.1016/j.tet.2005.09.025
日期:2005.11
The synthesis of the spirocyclic sesquiterpenes (-)-gleenol and (-)-axenol in enantiomerically pure form has been achieved starting from R-(-)-carvone. The key step is the silicon guided acid-promoted rearrangement of a 9-trimethylsilyl-5,6-epoxy-noreudesmane prepared from 3-tiimethylsilyldihydrocarvone in several steps involving Robinson annulation, enone deconjugation and epoxidation. Acid treatment of the epoxy-noreudesmane gave a norspiroaxane as the main product, which was used as intermediate for the synthesis of two naturally occurring sesquiterpenes gleenol and axenol. (c) 2005 Elsevier Ltd. All rights reserved.