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DOI: 10.1055/s-0037-1609586
Ti(III)-Mediated Radical-Induced Approach to a Bicyclic δ-Lactone with a Bridgehead β-Hydroxy Group
Publication History
Received: 21 June 2018
Accepted after revision: 25 June 2018
Publication Date:
05 July 2018 (online)


Published as part of the Special Topic Modern Radical Methods and their Strategic Applications in Synthesis
Abstract
Herein, we portray a synthetic route to a bicyclic lactone containing a bridgehead hydroxy group, a structure that is present in many natural products of biological and medicinal relevance. Ethyl (E)-3-(dimethylphenylsilyl)-7,8-epoxyoct-2-enoate underwent radical-mediated reductive epoxide opening with concomitant intramolecular cyclization using Cp2Ti(III)Cl to give cis-6-(dimethylphenylsilyl)-3-oxabicyclo[4.3.0]nonan-4-one, a bicyclic lactone with a bridgehead silyl group serving as a masked hydroxy group. Furthermore, the bridgehead C–Si bond underwent stereoretentive oxidative cleavage to give cis-6-hydroxy-3-oxabicyclo[4.3.0]nonan-4-one in high yield under Tamao–Fleming oxidation conditions; this demonstrates the potential utility of this strategy in the synthesis of many natural products bearing similar hydroxylated bridgehead chiral center embedded in a bicyclic lactone framework.
Key words
quaternary center - bridgehead hydroxy - Cp2TiCl - bicyclic lactone - radical cyclization - Tamao–Fleming oxidationSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0037-1609586.
- Supporting Information