N-Heterocyclic Carbene-Catalyzed Ireland–Coates Claisen Rearrangement: Synthesis of Functionalized β-Lactones
摘要:
The N-heterocyclic carbene (NHC)-catalyzed Claisen rearrangement of hybrid Ireland-Coates structures has been achieved, allowing the stereoselective synthesis of highly functionalized beta-lactones. The reaction proceeds with high diastereoselectivity (>20:1) and affords a diverse range of beta-lactone fused cyclopentanes. Mechanistic studies are detailed.
<i>N</i>-<i>tert</i>-Butyl Triazolylidenes: Catalysts for the Enantioselective (3+2) Annulation of α,β-Unsaturated Acyl Azoliums
作者:Lisa Candish、Craig M. Forsyth、David W. Lupton
DOI:10.1002/anie.201304081
日期:2013.8.26
range of N‐tert‐butyl‐substituted triazolylidene N‐heterocyclic carbenes have been prepared. Of these, the morpholinone‐derived catalyst (1) proved best suited to the enantioselective synthesis of cyclopentanes from donor–acceptor cyclopropanes and α,β‐unsaturated acyl fluorides. The performance of this catalyst has been correlated to the electronic nature of the catalyst by 13C NMR analysis. M.S.=molecular
但(基)不徒劳:的范围ñ -叔已经制备丁基取代triazolylidene N-杂环卡宾。其中,吗啉酮衍生的催化剂(1)被证明最适合从供体-受体环丙烷和α,β-不饱和酰基氟对映体选择性合成环戊烷。通过13 C NMR分析,该催化剂的性能与催化剂的电子性质相关。MS =分子筛,TMS =三甲基甲硅烷基。