Virtually Complete E-Selective α,β-Unsaturated Ester Synthesis by Hg(OTf)2-Catalyzed Hydration of sec-Ethoxyalkynyl Acetate
摘要:
The reaction of alkyl-substituted sec-ethoxyalkynyl acetates with water catalyzed by Hg(OTf)(2) afforded alpha,beta-unsaturated esters in excellent yield with high catalytic turnover up to 1000 times under very mild reaction conditions with virtually complete E-selectivity, superior even to that of the HWE reaction.
Rearrangement of Propargylic Esters: Metal-Based Stereospecific Synthesis of (<i>E</i>)- and (Z)-Knoevenagel Derivatives
作者:José Barluenga、Lorena Riesgo、Rubén Vicente、Luis A. López、Miguel Tomás
DOI:10.1021/ja072864r
日期:2007.6.1
catalysts perform the isomerization with complementary Z/E selectivity. Moreover, alkynyl-conjugated Knoevenagel products are produced from (bisalkynyl)methyl acetates. In such a case, the reaction is chemoselective as the 1,3-acetyl migration takes place through the alkoxyalkyne group in preference over the phenylalkyne group. The resulting (E)-alkynylenone unit suffers metal-catalyzed cyclization