β-Olefination of 2-Alkynoates Leading to Trisubstituted 1,3-Dienes
作者:Mathias J. Jacobsen、Erik Daa Funder、Jacob R. Cramer、Kurt V. Gothelf
DOI:10.1021/ol2011677
日期:2011.7.1
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 delta-position. Proof of concept is shown for the generation of a beta,gamma-unsaturated lactone by intramolecular olefination, and furthermore the use of the generated 1,3-dienes in the Diels-Alder reaction has been demonstrated.
Phosphine-Mediated Olefination between Aldehydes and Allenes: An Efficient Synthesis of Trisubstituted 1,3-Dienes with High <i>E</i>-Selectivity
作者:Silong Xu、Lili Zhou、San Zeng、Renqin Ma、Zhihong Wang、Zhengjie He
DOI:10.1021/ol901334c
日期:2009.8.6
The phosphine-mediated olefination of aldehydes with electron-deficient allenes to afford trisubstituted conjugated dienes in fair to excellent yields with high E-selectivity is described. The reaction represents a newreactivity pattern of allenes with aldehydes and also provides a highly stereoselective synthetic method for preparing conjugated dienes. In the reaction, the phosphine acts as a nucleophilic