Enantioselective N-Heterocyclic Carbene-Catalyzed Annulations of 2-Bromoenals with 1,3-Dicarbonyl Compounds and Enamines<i>via</i>Chiral α,β-Unsaturated Acylazoliums
作者:Santhivardhana Reddy Yetra、Anup Bhunia、Atanu Patra、Manoj V. Mane、Kumar Vanka、Akkattu T. Biju
DOI:10.1002/adsc.201300219
日期:2013.4.15
The N‐heterocyclic carbene (NHC)‐catalyzed generation of chiral α,β‐unsaturated acylazoliums from 2‐bromoenals followed by their interception with 1,3‐dicarbonyl compounds or enamines, the formal [3+3] annulation reaction, is reported. The reaction results in the enantioselective synthesis of synthetically and medicinally important dihydropyranones and dihydropyridinones, and tolerates a wide range
据报道,N-杂环卡宾(NHC)催化了从2-溴烯醛中生成手性α,β-不饱和酰基la,然后被1,3-二羰基化合物或烯胺截获,这是正式的[3 + 3]环化反应。该反应导致合成上和医学上重要的二氢吡喃酮和二氢吡啶并酮的对映选择性合成,并具有宽泛的官能团。值得注意的是,该反应在温和的反应条件下利用相对较低的催化剂负载量进行。此外,基于DFT计算,提出了一种机制方案,涉及亲核试剂从α,β-不饱和酰基环的平面下方攻击,以及对映体诱导的模式。