Catalytic Asymmetric Chlorination ofβ-Keto Esters with Hypervalent Iodine Compounds
作者:Hasim Ibrahim、Florian Kleinbeck、Antonio Togni
DOI:10.1002/hlca.200490058
日期:2004.3
(Dichloroiodo)toluene (=dichloro(4-methylphenyl)iodine; 2) was found to be a suitable chlorinating agent in the catalytic asymmetric chlorination of β-keto esters 3 catalyzed by the [Ti(TADDOLato)] complex 1 (=bis(acetonitrile)dichloro[(4R,5R)-2,2-dimethyl-α,α,α′,α′-tetra(naphthalen-1-yl)-1,3-dioxolane-4,5-dimethanolato(2−)-κO,κO′]titanium), whereby α-chlorinated products were obtained in moderate
(Dichloroiodo)甲苯(=二氯(4-甲基苯基)碘; 2)被认为是在催化不对称氯化合适的氯化剂β酮酯3催化由钛[Ti(TADDOLato)]络合物1(=双(乙腈)二氯[(4 R,5 R)-2,2-二甲基-α,α,α ',α'-四(萘-1-基)-1,3-二氧戊环-4,5-二甲醇(2 −)- κO,κO ']钛),从而以中等至良好的产率获得α-氯化产物,对映选择性高达71%(方案2,表2)。反应的对映选择性显示出显着的温度依赖性,最大选择性在约200 ℃下获得。50°。