Fe(III) catalyzed enantioselective hydrophosphonylation of aldehydes promoted by chiral camphor Schiff bases

Five novel chiral camphor Schiff bases were designed. Schiff base L3 showed high efficiency in Fe(III)-catalyzed asymmetric hydrophosphonylations of aldehydes, giving the corresponding products in high yields (up to 91%) along with moderate to good enantioselectivities (up to 82%).

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(1S,2R,4R)-1-(2-Hydroxybenzylideneamino)-7,7-dimethyl-bicyclo[2.2.1]heptan-2-olC16H21NO2[α]D22 = −110.8 (c 1.0, CHCl3)Absolute configuration: (1S,2R,4R)

(1S,2R,4R)-1-(2-Hydroxy-3-methoxybenzylideneamino)-7,7-dimethylbicyclo[2.2.1]heptan-2-olC17H23NO3[α]D22 = −157.2 (c 1.0, CHCl3)Absolute configuration: (1S,2R,4R)

(1S,2R,4R)-1-(2-Hydroxy-3-methylbenzylideneamino)-7,7-dimethylbicyclo[2.2.1]heptan-2-olC17H23NO2[α]D22 = −56.1 (c 1.0, CHCl3)Absolute configuration: (1S,2R,4R)

(1S,2R,4R)-1-((E)-3,5-Di-tert-butyl-2-hydroxybenzylidene-amino)-7,7-dimethylbicyclo[2.2.1]heptan-2-olC24H37NO2[α]D22 = −51.4 (c 1.0, CHCl3)Absolute configuration: (1S,2R,4R)

4-((E)-((1S,2R,4R)-2-Hydroxy-7,7-dimethylbicyclo[2.2.1]-heptan-1-ylimino)methyl)benzene-1,3-diolC16H21NO3[α]D22 = −175.1 (c 1.0, CHCl3)Absolute configuration: (1S,2R,4R)