Asymmetric Mannich reactions catalyzed by cinchona alkaloid thiourea: enantioselective one-pot synthesis of novel β-amino ester derivatives

An efficient one-pot synthesis of novel β-amino ester derivatives containing a benzoxazol moiety has been developed by using cinchona alkaloid thioureas as the organocatalyst. The adducts were isolated in high enantiomeric excess and high yield.

An efficient one-pot synthesis of novel β-amino ester derivatives containing benzoxazol moiety has been developed by using cinchona alkaloid thiourea as the organocatalyst. The adducts were isolated in high enantiomeric excess and yield.Figure optionsDownload as PowerPoint slide

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(phenyl)methyl)malonateC21H21ClN2O5[α]D25=-12.2 (c 0.70, CHCl3)87.8% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(2-fluorophenyl)methyl)malonateC21H20ClFN2O5[α]D25=-15.0 (c 0.80, CHCl3)94.4% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(2-chlorophenyl)methyl)malonateC21H20Cl2N2O5[α]D25=-80.9 (c 0.77, CHCl3)90.5% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(cyclohexyl)methyl)malonateC21H27ClN2O5[α]D25=+48.5 (c 1.50, CHCl3)93.0% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(2,6-dichlorophenyl)methyl)malonateC21H19Cl3N2O5[α]D25=-78.1 (c 0.80, CHCl3)81.2% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(2,5-dimethoxyphenyl)methyl)malonateC23H25ClN2O7[α]D25=-41.7 (c 0.65, CHCl3)86.7% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(3-chlorophenyl)methyl)malonateC21H20Cl2N2O5[α]D25=+106.1 (c 0.85, CHCl3)89.3% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(1-((5-chlorobenzo[d]oxazol-2-yl)amino)butyl)malonateC18H23ClN2O5[α]D25=-42.6 (c 0.63, CHCl3)> 99% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Diethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(p-tolyl)methyl)malonateC22H23ClN2O5[α]D25=+45.8 (c 1.15, CHCl3)90.9% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Dimethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(cyclohexyl)methyl)malonateC19H23ClN2O5[α]D25=+51.7 (c 0.75, CHCl3)96.2% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Dimethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(3-fluorophenyl)methyl)malonateC19H16ClFN2O5[α]D25=+23.1 (c 1.00, CHCl3)89.0% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Dimethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(phenyl)methyl)malonateC19H17ClN2O5[α]D25=-34.9 (c 0.75, CHCl3)87.7% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Dimethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(2,6-dichlorophenyl)methyl)malonateC19H15Cl3N2O5[α]D25=-64.9 (c 0.90, CHCl3)92.7% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown

Dimethyl 2-(((5-chlorobenzo[d]oxazol-2-yl)amino)(2-fluorophenyl)methyl)malonateC19H16ClFN2O5[α]D25=-12.6 (c 0.75, CHCl3)88.0% eeSource of chirality: asymmetric synthesisAbsolute configuration: unknown