Asymmetric Ring-Closing Metathesis Catalyzed by Chiral Molybdenum Alkylidene Complexes
作者:Osamu Fujimura、Robert H. Grubbs
DOI:10.1021/jo971952z
日期:1998.2.1
2-bis(2'-hydroxyethyl)cyclohexane). In the case of a prochiral symmetric triene substrate, optically active cyclized product was formed by catalytic ring-closing metathesis with 1, which opens the possibility of a new version of two-directional synthesis. Although the observed enantiomeric excesses were modest to low, this data demonstrates the feasibility of asymmetric induction by chiral alkylidene catalysts
在新开发的手性钼亚烷基络合物(R,R)-Mo(CHCMe(2)Ph)(NAr)(TBEC)1(Ar = 2,6-i)催化下,外消旋二烯的闭环易位反应中观察到动力学拆分-Pr(2)C(6)H(3),TBEC = 2',2',2“,2”-四(三氟甲基)-1,2-双(2'-羟乙基)环戊烷)和(R, R)-Mo(CHCMe(2)Ph)(NAr)(TBEH)2(Ar = 2,6-i-Pr(2)C(6)H(3),TBEH = 2',2',2“ ,2″-四(三氟甲基)-1,2-双(2′-羟乙基)环己烷)。在前手性对称三烯底物的情况下,光学活性环化产物是通过催化闭环复分解反应与1形成的,这为双向合成的新形式打开了可能性。尽管观察到的对映体过量适度至低,