ChemInform Abstract: Asymmetric Addition of Phenylzinc Reagents to C‐Alkynyl Nitrones. Enantiomeric Enhancement by a Product‐Like Additive.

Abstract

Hydroxylamine derivatives Q 0110Asymmetric Addition of Phenylzinc Reagents to C-Alkynyl Nitrones. Enantiomeric Enhancement by a Product-Like Additive. -Chiral hydroxylamines (III) are formed by the addition of either diphenylzinc or phenyl(methyl)zinc to alkynyl nitrones in the presence of TAR as chiral auxiliary. Catalytic amounts of racemic product-like HYA enhance the enantioselectivity. In several cases, the application of PhZnMe gives higher enantioselectivities than ZnPh2. Catalytic amounts of HYA also significantly improve the enantioselectivity of the addition of ZnPh 2 to C-alkenyl nitrone (V). -(WEI, W.; HAMAMOTO, Y.; UKAJI*, Y.; INOMATA, K.; Tetrahedron: Asymmetry 19 (2008) 4, 476-481; Div. Mater. Sci., Grad. Sch. Nat. Sci. Technol., Kanazawa Univ., Kanazawa 920, Japan; Eng.) -Klein 37-065