H-Bonding Additives Act Like Lewis Acid Catalysts

作者：Peter R. Schreiner, Alexander Wittkopp · 发表于：Organic Letters · 年份：2002 · DOI：10.1021/ol017117s · 被引用次数：473 · 研究领域：Asymmetric Synthesis and Catalysis、Crystallography and molecular interactions、Organometallic Complex Synthesis and Catalysis

[reaction: see text] A combination of NMR, IR, and ab initio techniques reveals the striking structural similarities of an exemplary H-bonded complex of an N-acyloxazolidinone with an N,N'-disubstituted electron-poor thiourea and the corresponding Lewis acid complex. Although the H-bond association constant is lower than for the Lewis acid adduct, Diels-Alder reactions are accelerated and stereochemically altered in a fashion similar to weak Lewis acids.