Rommel Michael, Fukuzumi Takeo, Bode Jeffrey W
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
J Am Chem Soc. 2008 Dec 24;130(51):17266-7. doi: 10.1021/ja807937m.
Cyclic sulfonyl imines derived from ketones were identified as stable and readily prepared compounds that serve as superior electrophiles for N-heterocyclic carbene (NHC)-catalyzed annulations with alpha,beta-unsaturated aldehydes to afford highly substituted gamma-lactams. Their superior reactivity and properties are highlighted by the first example of NHC-catalyzed reactions of enals with low catalyst loadings (0.5 mol %) and broad substrate scope encompassing alkyl, aryl, and heteroaromatic substituents. These findings and supporting studies suggest an alternative, ene-like mechanism rather than the catalytic generation of a catalyst-bound homoenolate equivalent.
源自酮的环状磺酰亚胺被鉴定为稳定且易于制备的化合物，它们作为优良的亲电试剂，用于与α,β-不饱和醛进行N-杂环卡宾（NHC）催化的环化反应，以得到高度取代的γ-内酰胺。在低催化剂负载量（0.5 mol%）的烯醛NHC催化反应的首个实例以及涵盖烷基、芳基和杂芳基取代基的广泛底物范围中，突出显示了它们卓越的反应活性和性质。这些发现及辅助研究表明存在一种替代的、类似烯反应的机制，而非催化生成与催化剂结合的同系烯醇盐等价物。
