For Abstract see ChemInform Abstract in Full Text.

The enantioselective 1,3-dipolar cycloaddition reaction of nitrones with α,β-unsaturated aldehydes was realized using 3-oxobutylideneaminatocobalt complex catalysts. Varieties of the cobalt(II) and cobalt(III) complexes were screened and the cationic cobalt(III) complex with hexafluoroantimonate was found to be the most effective for the catalytic enantioselective 1,3-dipolar cycloaddition reaction. In the presence of the cobalt(III) hexafluoroantimonate complex, the enantioselective 1,3-dipolar cycloaddition reaction of various nitrones with α,β-unsaturated aldehydes afforded the corresponding isoxazolidines in high yields and with high enantioselectivities. The absolute configuration of the optically active products was determined by X-ray analysis. Reasonable explanations for the enantioselection in the present 1,3-dipolar cycloaddition reaction catalyzed by the 3-oxobutylideneaminatocobalt complex were proposed.

Alcohols Q 0230Enantioselective Henry Reaction Catalyzed by Salen-Cobalt Complexes. -Aldehydes of type (I) and (IV) undergo the Henry reaction catalyzed by optically active salen-cobalt complexes to afford (R)-β-hydroxynitroalkanes (III) or (V) in good or high yields with high enantioselectivity. -(KOGAMI, Y.; NAKAJIMA, T.; IKENO, T.; YAMADA*, T.; Synthesis 2004Synthesis , 12, 1947Synthesis -1950 Dep. Chem., Fac. Sci. Technol., Keio Univ., Kohoku, Yokohama 223, Japan; Eng.) -M. Bohle 51-070

For Abstract see ChemInform Abstract in Full Text.

The enantioselective Henry reaction catalyzed by the optically active salen-cobalt complexes, proceeded to afford bhydroxynitroalkanes in good-to-high yields with high enantioselectivity.