Synthesis of New Chiral Derivatives of N,N′-Dimethylpropyleneurea (DMPU) and Examination of Their Influence on the Regio- and Enantioselectivity of Addition of 2-(1,3-Dithianyl)lithium to Cyclohex-2-en-1-one
作者:Eusebio Juaristi、Marcos Hernández-Rodríguez、Heraclio López-Ruiz、Judit Aviña、Omar Muñoz-Muñiz、Michiya Hayakawa、Dieter Seebach
DOI:10.1002/1522-2675(200207)85:7<1999::aid-hlca1999>3.0.co;2-k
日期:2002.7
another type of derivative is substituted at C(4) and C(6) of the heterocyclic ring (7). The potential of these chiral Lewis bases as promoters in the regio- and/or enantioselective addition of 2-(1,3-dithianyl)lithium to cyclohex-2-en-1-one was explored; they are all unable to effect enantioselective addition; the derivatives with branched substituents at the N-atoms do not shift the addition mode from
描述了三种新的 DMPU 手性衍生物(N,N'-二甲基丙烯脲)的制备(方案 2-4);一种衍生物在四氢嘧啶-2(1H)-一个环 (2 和 4) 的 N 原子上带有 1-苯乙基或 1-环己基乙基,另一种衍生物在 C(4) 和 C(6) 处被取代) 的杂环 (7)。探索了这些手性路易斯碱在 2-(1,3-二噻吩基)锂与 cyclohex-2-en-1-one 的区域选择性和/或对映选择性加成中作为促进剂的潜力;它们都不能实现对映选择性加成;在 N 原子上具有支化取代基的衍生物不会将加成模式从 1,2 转变为 1,4,而 3,4,5,6-tetrahydro-1,3,4,6-tetramethylpyrimidin-2(1H )-一个可以(方案 5)。结果提供了有关亲核有机锂试剂性质的有用信息:显然,N 原子上的支链取代基对四氢嘧啶-2(1H)-one 的 CO O 原子上的 Li 络合的空间位阻(参见图中