Asymmetric Vinylogous Aldol Reaction of Silyloxy Furans with a Chiral Organic Salt
作者:Ravi P. Singh、Bruce M. Foxman、Li Deng
DOI:10.1021/ja103331t
日期:2010.7.21
significance there is a general lack of asymmetric vinylogous aldolreactions that tolerate variations of both the silyloxy furans and aldehydes. We have developed a newchiral organic catalyst based on a carboxylate-ammonium salt preparedfrom a thiourea-amine and a carboxylic acid. This newcatalyst enabled us to develop an efficient asymmetric vinylogous aldolreaction of unprecedented scope with respect
Chiral Quaternary Ammonium Aryloxide/<i>N,O</i>-Bis(trimethyl- silyl)acetamide Combination as Efficient Organocatalytic System for the Direct Vinylogous Aldol Reaction of (<i>5H</i>)-Furan-2-one Derivatives
A chiralquaternaryammonium amide was generated in situ from N,O‐bis(trimethylsilyl)acetamide (BSA) as non‐nucleophilic Brønsted base precursor and the combination of chiralquaternaryammonium halide/sodium aryloxide as chiral Lewis base. This system was applied to an anti‐selective organocatalyticdirectvinylogousaldol (ODVA) reaction of (5H)‐furan‐2‐one derivatives with aldehydes. Several 5‐