Enantioselective synthesis of (R)-Sumanirole using organocatalytic asymmetric aziridination of an α,β-unsaturated aldehyde

Herein we report an enantioselective synthesis of (R)-Sumanirole wherein an organocatalytic asymmetric aziridination of 2-nitrocinnamaldehyde was the key step.

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tert-Butyl (2R,3S)-2-formyl-3-(2-nitrophenyl)aziridine-1-carboxylateC14H16N2O5Ee = 97%[α]D20 = +59.7 (c 1.01, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (2R,3S)

1-(tert-Butyl) 2-methyl (2R,3S)-3-(2-nitrophenyl)aziridine-1,2-dicarboxylateC15H18N2O6Ee = 97%[α]D16 = +20.4 (c 0.95, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (2R,3S)

tert-Butyl (R)-(2-oxo-1,2,3,4-tetrahydroquinolin-3-yl)carbamateC14H18N2O3Ee = 97%[α]D25 = −2.0 (c 0.50, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

tert-Butyl (R)-(1,2,3,4-tetrahydroquinolin-3-yl)carbamateC14H20N2O2Ee = 97%[α]D24 = +7.9 (c 0.50, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

tert-Butyl (R)-(1-(methoxycarbamoyl)-1,2,3,4-tetrahydroquinolin-3-yl)carbamateC16H23N3O4Ee = 97%[α]D25 = +21.9 (c 0.50, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

tert-Butyl (R)-(1-methoxy-2-oxo-1,2,5,6-tetrahydro-4H-imidazo[4,5,1-ij]quinolin-5-yl)carbamateC16H21N3O4Ee = 97%[α]D25 = +6.0 (c 0.50, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

tert-Butyl (R)-(1-methoxy-2-oxo-1,2,5,6-tetrahydro-4H-imidazo[4,5,1-ij]quinolin-5-yl)carbamateC17H23N3O4Ee = 97%[α]D25 = +37.9 (c 0.50, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

(1R)-2-Phenyl-2-cyclopenten-1-yl malonic acid dibenzyl esterC16H21N3O3Ee = 97%[α]D24 = +29.5 (c 0.25, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

(R)-5-(Methylamino)-5,6-dihydro-4H-imidazo[4,5,1-ij]quinolin-2(1H)-one hydrochlorideC11H13ClN3OEe = 97%[α]D25 = −29.0 (c 0.43, MeOH)Source of chirality: asymmetric synthesisAbsolute configuration: (R)