Organic Letters 2011-07-01

β-Olefination of 2-alkynoates leading to trisubstituted 1,3-dienes.

Mathias J Jacobsen, Erik Daa Funder, Jacob R Cramer, Kurt V Gothelf

Index: Org. Lett. 13(13) , 3418-21, (2011)

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Abstract

A phosphine-mediated olefination of 2-alkynoates with aldehydes forming 1,3-dienes with high E-selectivity and up to 88% yield is described. Reaction conditions are optimized and reactions are demonstrated for various aryl, alkyl, and alkenyl aldehydes and for ethyl 2-alkynoates with different substituents in the δ-position. Proof of concept is shown for the generation of a β,γ-unsaturated lactone by intramolecular olefination, and furthermore the use of the generated 1,3-dienes in the Diels-Alder reaction has been demonstrated.