Rhodium/chiral diene-catalyzed asymmetric methylation of N-sulfonylarylimines with trimethylboroxine

A hydroxorhodium complex coordinated with a chiral diene ligand catalyzed the asymmetric addition of trimethylboroxine to N-sulfonylarylimines to give high yields of chiral 1-aryl-1-ethylamines with high enantioselectivity.

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N-(1-(4-Chlorophenyl)ethyl)-4-methylbenzenesulfonamideC15H16ClNO2SEe = 99%[α]D20=-79 (c 0.55, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(3-Chlorophenyl)ethyl)-4-methylbenzenesulfonamideC15H16ClNO2SEe = 98%[α]D20=-73 (c 0.50, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(2-Chlorophenyl)ethyl)-4-methylbenzenesulfonamideC15H16ClNO2SEe = 99%[α]D20=-53 (c 0.40, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(4-Bromophenyl)ethyl)-4-methylbenzenesulfonamideC15H16BrNO2SEe = 98%[α]D20=-62 (c 0.33, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

4-Methyl-N-(1-(4-(trifluoromethyl)phenyl)ethyl)benzene-sulfonamideC16H16F3NO2SEe = 99%[α]D20=-49 (c 0.51, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(4-Methoxyphenyl)ethyl)-4-methylbenzenesulfonamideC16H19NO3SEe = 99%[α]D20=-82 (c 0.51, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(2-Methoxyphenyl)ethyl)-4-methylbenzenesulfonamideC16H19NO3SEe = 98%[α]D20=-66 (c 0.42, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

4-Methyl-N-(1-(naphthalen-1-yl)ethyl)benzenesulfonamideC19H19NO2SEe = 97%[α]D20=+14 (c 0.52, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

4-Methyl-N-(1-(naphthalen-2-yl)ethyl)benzenesulfonamideC19H19NO2SEe = 98%[α]D20=-79 (c 0.46, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(4-Chlorophenyl)ethyl)-4-nitrobenzenesulfonamideC14H13ClN2O4SEe = 98%[α]D20=-37 (c 0.56, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)

N-(1-(4-Methoxyphenyl)ethyl)-4-nitrobenzenesulfonamideC15H16N2O5SEe = 98%[α]D20=-32 (c 0.47, CHCl3).Source of chirality: asymmetric methylationAbsolute configuration: (S)