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6845554 
Journal Article 
ENANTIOSELECTIVE PREPARATION OF SEC ALCOHOLS FROM ALDEHYDES AND DIALKYL ZINC-COMPOUNDS, GENERATED INSITU FROM GRIGNARD-REAGENTS, USING SUBSTOICHIOMETRIC AMOUNTS OF TADDOL-TITANATES 
Busschehunnefeld, JLV; Busschehunnefeld, JLV; Seebach, D; Seebach, D 
1992 
1 
Tetrahedron
ISSN: 0040-4020 
48 
27 
5719-5730 
WOS:A1992JB96000019 
Using 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 tum 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 alpha,alpha,alpha',alpha'-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL). Grignard reagents containing remote double bonds, benzene rings, or acetal groups can also be employed. Different TADDOLs are compared with respect to their usefulness in this kind of enantioselective reaction.<