Organocatalytic Enantioselective Dipolar [3+2] Cycloadditions of Acetylenic Aldehydes with Nitrones for the Formation of Chiral 4-Isoxazolines
作者:Xianrong Cai、Chao Wang、Jian Sun
DOI:10.1002/adsc.201100351
日期:2012.2
organocatalytic enantioselective protocol has been developed for the dipolar [3+2] cycloaddition between acetylenic aldehydes and nitrones through an iminium activation pathway. This protocol uses L-α,α-bis(3,5-ditrifluoromethylphenyl)prolinol as catalyst and 3,5-dinitrobenzoic acid as additive and is friendly for one-pot operation for the nitrone formation and the subsequent cycloaddition. It also exhibits
已经开发出第一个有机催化对映选择性方案,用于通过亚胺基活化途径在乙炔醛和硝酮之间进行偶极[3 + 2]环加成。该方案使用L-α,α-双(3,5-二三氟甲基苯基)脯氨醇作为催化剂,并使用3,5-二硝基苯甲酸作为添加剂,对于一锅操作形成硝酮和随后的环加成反应是友好的。它还具有广泛的底物范围,并允许在温和条件下以高产率(68-92%)和高对映选择性(高达96%ee)高效生产具有各种取代基的手性4-异恶唑啉。