Efficient Synthesis of 4-(3′-Furanyl)butenolide Derivatives via PdII-Catalyzed Oxidative Heterodimeric Cyclization Reaction of 2,3-Allenoic Acids and 1,2-Allenyl Ketones
作者:Shengming Ma、Zhanqian Yu
DOI:10.1002/chem.200305341
日期:2004.4.19
conveniently through chiral resolution with optically active amines, that is, cinchonidine or alpha-methyl benzylamine. A mechanistic study showed that the reaction proceeded via a matched double oxypalladation-reductive elimination process. The Pd(II) species may be regenerated via the subsequent cyclometallation of two equivalents of 1,2-allenyl ketones with Pd(0) and protonlysis of Pd enolates formed with the
据报道,具有不同官能度的两类丙二烯之间的氧化环化/二聚反应为多取代的4-(3'-呋喃基)-2(5H)-呋喃酮提供了一条有效的途径,而该方法无法从已知方法中轻易获得。旋光性高的丁烯化物可以很容易地由旋光性的2,3-烯丙酸形成,这可以通过旋光拆分与旋光性胺,即辛可尼丁或α-甲基苄基胺方便地获得。机理研究表明,该反应通过匹配的双氧钯还原-还原消除过程进行。可以通过随后的两个当量的1,2-烯基酮与Pd(0)的环金属化作用以及由原位生成的HCl形成的Pd烯醇化物的质子化来再生Pd(II)物种。