Nickel(0)-Catalyzed Enantioselective Annulations of Alkynes and Arylenoates Enabled by a Chiral NHC Ligand: Efficient Access to Cyclopentenones
作者:Joachim S. E. Ahlin、Pavel A. Donets、Nicolai Cramer
DOI:10.1002/anie.201408364
日期:2014.11.24
nickel‐catalyzed reductive [3+2] cycloaddition of α,β‐unsaturated aromatic esters and alkynes constitutes an efficient method for their synthesis. Here, nickel(0) catalysts comprising a chiral bulky C1‐symmetric N‐heterocyclic carbene ligand were shown to enable an efficient asymmetric synthesis of cyclopentenones from mesityl enoates and internal alkynes under mild conditions. The bulky NHC ligand
环戊烯酮是天然产物以及反应性合成中间体的多功能结构基序。镍催化的α,β-不饱和芳族酯和炔烃的还原[3 + 2]环加成反应是合成它们的有效方法。在这里,包含手性庞大的C 1-对称的N-杂环卡宾配体的镍(0)催化剂被证明能够在温和的条件下由均三烯酸酯和内部炔烃有效地不对称合成环戊烯酮。庞大的NHC配体以非常高的对映选择性提供了环戊烯酮产物,并导致不对称取代的炔烃的区域选择性结合。