Some new C2-symmetric bicyclo[2.2.1]heptadiene ligands: synthesis and catalytic activity in rhodium(I)-catalyzed asymmetric 1,4- and 1,2-additions
作者:Timothy Noël、Koen Vandyck、Johan Van der Eycken
DOI:10.1016/j.tet.2007.10.034
日期:2007.12
C2-Symmetric bicyclo[2.2.1]hepta-2,5-dienes with various substituents (R=Bn, i-Bu, c-Hex, allyl) are prepared starting from the corresponding enantiomerically pure bis-triflate (R=OTf). These chiral ligands are tested and compared in rhodium(I)-catalyzed 1,4- and 1,2-addition of phenylboronic acid to cyclic enones and aryl aldehydes, respectively. Some interesting reactivity and selectivity effects
从相应的对映体纯的双三氟甲磺酸酯(R = OTf)开始制备具有各种取代基(R = Bn,1 - Bu,c- Hex,烯丙基)的C 2对称双环[2.2.1]庚-2,5-二烯。)。对这些手性配体进行了测试,并在铑(I)催化的苯基硼酸分别向环烯酮和芳基醛的1,4-和1,2-加成中进行了比较。据报道由于引入空间上需要的或烯烃取代基而引起的一些有趣的反应性和选择性作用。此外,对于铑(I)催化的1,2-加成观察到非常高的催化活性。