the Schlenk trick (precipitation of MgX2 from ethereal solutions by the addition of 1,4-dioxane) mixtures of a Grignard reagent RMgX (X = Cl, Br, I) and 0.5 equiv. ZnCl2 in Et2O can be converted to zinc alkyls R2Zn which in turn are added with enantio-selectivities of up to 99 : 1 to aliphatic and aromatic aldehydes in the presence of Ti(OCHMe2)4 and a chiral titanate derived from an α,α,α′,α′-tetraaryl-1
使用Schlenk技巧(通过添加1,4-
二恶烷,从醚溶液中沉淀出MgX 2),将
格氏试剂RMgX(X = Cl,Br,I)和0.5当量的混合物。可以将Et 2 O中的ZnCl 2转化为烷基
锌R 2 Zn,然后在Ti(OCHMe 2)4和手性
钛酸酯的存在下,将脂族和芳族醛的对映选择性高达99:1。由α,α,α',α'-四芳基-
1,3-二氧戊环-4,5-二
甲醇(TADDOL)制得。
格氏试剂盒也可以使用双键,苯环或
缩醛基。比较了不同的TADDOL在这类对映选择性反应中的用途。