Chiral DBFOX/Ph complex catalyzed enantioselective nitrone cycloadditions to alpha,beta-unsaturated aldehydes.
1,3-Dipolar cycloadditions of nitrones with alpha-alkyl- and alpha-arylacroleins are catalyzed with the DBFOX/Ph complexes of nickel(II) and magnesium(II) salts to produce the sterically controlled isoxazolidine-5-carbaldehydes, while the reactions with alpha-bromoacrolein are effectively catalyzed with the zinc(II) complexes to produce the electronically controlled isoxazolidine-4-carbaldehydes. Enantioselectivities up to 99.5% ee have been observed in the reactions performed at room temperature. [reaction: see text]
Shirahase
Moto
M
Institute for Materials Chemistry and Engineering, CREST of JST (Japan Science and Technology Agency), Kyushu University, 6-1 Kasugakoen, Kasuga 816-8580, Japan,
Kanemasa
Shuji
S
Oderaotoshi
Yoji
Y