Lewis Acid Catalyzed Allylboration: Discovery, Optimization, and Application to the Formation of Stereogenic Quaternary Carbon Centers
作者:Jason W. J. Kennedy、Dennis G. Hall
DOI:10.1021/jo049773m
日期:2004.6.1
A full account of the development of the first catalytic manifold for the additions of allylboronates to aldehydes is described. The thermal additions (both diastereospecific and enantioselective) of 2-carboxyester 3,3-disubstituted allylboronates 1 to both aromatic and aliphatic aldehydes give biologically and synthetically important exo-methylene butyrolactones 2 containing a β-quaternary carbon
描述了将烯丙基硼酸酯加成到醛中的第一催化歧管的发展的完整说明。将2-羧酸酯3,3-二取代的烯丙基硼酸酯1热加成(非对映体特异性和对映体选择性)对芳香族和脂肪族醛均具有生物学和合成意义的外亚甲基丁内酯2包含一个β-季碳中心。尽管热反应在室温下需要14 d才能完成,但是某些金属盐的存在可以使反应12-16 h,同时保留未催化过程中观察到的非对映特异性。描述了对催化作用起源的初步机理研究,以及内酯2立体选择性转化为环状和非环状的立体三单元体,具有潜在的合成中间体用途。