Model studies for a ring-closing metathesis approach to the Bafilomycin macrolactone core from a 2,2-dimethoxy tetraenic ester precursor

Chevalley, A., Prunet, J. , Mauduit, M. and Ferezou, J.-P. (2013) Model studies for a ring-closing metathesis approach to the Bafilomycin macrolactone core from a 2,2-dimethoxy tetraenic ester precursor. European Journal of Organic Chemistry, 2013(36), pp. 8265-8278. (doi:10.1002/ejoc.201300559)

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Abstract

A ring-closing metathesis strategy is reported for the construction of the 16-membered macrolactone core of the bafilomycins. One decisive key feature is the presence of a 2,2-dimethoxyketal functionality at C-2 that provides the required flexibility to the tetraenic ester precursor, allowing the ring-closing metathesis reaction to take place. Three different model esters of increasing complexity were successfully subjected to the 1,3-diene-ene ring-closing metathesis reaction. The best promoter for the simplest esters was the Grubbs first-generation precatalyst. A Hoveyda–Grubbs-type trifluoromethylamido-containing precatalyst developed by Mauduit's group gave satisfactory results for the most complex ester. In all experiments, the 12-Z-configured isomer was obtained as the major product. Subsequent microwave-promoted methanol elimination was achieved on the simplest model compound using camphorsulfonic acid (CSA) as a catalyst. Under these conditions, a E to Z isomerization of the double bond at C-4, as well as ca. 50 % isomerization of the 12-Z double bond into the corresponding 12-E isomer, were observed.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Prunet, Dr Joelle
Authors: Chevalley, A., Prunet, J., Mauduit, M., and Ferezou, J.-P.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:European Journal of Organic Chemistry
Publisher:Wiley - V C H Verlag GmbH & Co. KGaA
ISSN:1434-193X
ISSN (Online):1099-0690

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