Scope and Limitation of Organocuprates, and Copper or Nickel Catalyst-Modified Grignard Reagents for Installation of an Alkyl Group onto <i>cis</i>-4-Cyclopentene-1,3-diol Monoacetate
作者:Michiko Ito、Michitaka Matsuumi、Modachur G. Murugesh、Yuichi Kobayashi
DOI:10.1021/jo010474w
日期:2001.8.1
NiCl(2)(tpp)(2), NiCl(2)(dppf), and NiCl(2)(dppp) furnished the best result to produce 2a. The CuCN-based protocol was then applied to other alkyl Grignard reagents, which include Me, Et, (CH(2))(3)Ph, c-C(6)H(11), (CH(2))(6)OMOM, (CH(2))(9)CH=CH(2), and CH(2)Ph as the alkyl group (R(T)). In addition, the Mitsunobu inversion of 2a and 3a afforded the corresponding cis isomers stereoselectively with AcOH
用两种类型的试剂研究了标题化合物1的烷基化。一种是衍生自R(T)MgX(X = Cl,Br)和CuX(X = CN,I)的铜试剂,另一种是在铜或镍催化剂存在下的R(T)MgX。首先,用BuCu(CN)(MgX),Bu(2)Cu(CN)(MgX)(2),BuMgX / CuCN(10 mol%),BuCu(衍生自BuMgCl和CuI)和BuMgCl /在THF或Et(2)O中的CuI(10 mol%)。我们发现反式1,4-异构体2a和/或反式1,2-异构体3a仅用这些试剂生产,BuMgX / CuX的化学计量和溶剂的选择对于获得高区域选择性和高效收率至关重要。与Bu(2)Cu(CN)(MgCl)(2)和BuMgCl / CuX(X = CN,I; 10 mol%)均在THF中反应生成2a,其区域选择性为93-94%,产率为87-92%。另一方面,BuCu(CN)(MgX)在THF中 Et(2