| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1346085 | Tetrahedron: Asymmetry | 2012 | 7 Pages |
A double catalyst system (protease + base) was applied to the dynamic kinetic resolution (DKR) of isomeric 1- and 2-α-naphthyl-glycines and -alanines exploiting the in situ racemization of their thioesters. Due to the different C-acidity of the two sets of compounds, different experimental conditions have been devised to perform the simultaneous resolution/racemization process.In all cases, the racemic N-Boc-thioesters were converted into the aminoacids with an l-configuration almost quantitatively and with complete enantioselectivity.
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(S)-S-Ethyl 2-(tert-butoxycarbonylamino)-3-(naphthalen-1-yl)propanethioateC20H25NO3S[α]D20=+58.5 (20 mg/2 mL 2-PrOH)Source of chirality: esterification of the corresponding N-Boc-aminoacidAbsolute configuration: (S)
(S)-S-Ethyl 2-(tert-butoxycarbonylamino)-2-(naphthalen-1-yl)propanethioateC19H23NO3S[α]D20=-141.9 (29 mg/2 mL 2-PrOH)Source of chirality: esterification of the corresponding N-Boc-aminoacidAbsolute configuration: (S)
(S)-S-Ethyl 2-(tert-butoxycarbonylamino)-3-(naphthalen-2-yl)propanethioateC20H25NO3S[α]D20=-39.7 (20 mg/2 mL 2-PrOH)Source of chirality: esterification of the corresponding N-Boc-aminoacidAbsolute configuration: (S)
(S)-S-Ethyl 2-(tert-butoxycarbonylamino)-2-(naphthalen-2-yl)-ethanethioateC19H23NO3S[α]D20=-104.6 (23 mg/2 mL 2-PrOH)Source of chirality: esterification of the corresponding N-Boc-aminoacidAbsolute configuration: (S)
(S)-2-(tert-Butoxycarbonylamino)-3-(naphthalen-1-yl)propanoic acidC18H21NO4[α]D20=-30.9 (18 mg/2 mL 2-PrOH)Source of chirality: DKR of d,l-1aAbsolute configuration: (S)
(S)-2-(tert-Butoxycarbonylamino)-2-(naphthalen-1-yl)ethanoic acidC17H19NO4[α]D20=+90.7 (16 mg/2 mL 2-PrOH)Source of chirality: DKR of d,l-2aAbsolute configuration: (S)
(S)-2-(tert-Butoxycarbonylamino)-3-(naphthalen-2-yl)propanoic acidC18H21NO4[α]D20=+45.0 (20 mg/2 mL CH3OH)Source of chirality: DKR of 3aAbsolute configuration: (S)
(S)-2-(tert-Butoxycarbonylamino)-2-(naphthalen-2-yl)ethanoic acidC17H19NO4[α]D20=+158.3 (19 mg/2 mL 2-PrOH)Source of chirality: DKR of d,l-4aAbsolute configuration: (S)
(S)-2-Amino-2-(naphthalen-1-yl)ethanoic acid hydrochlorideC12H12NO2Cl[α]D20=+26.6 (20 mg/2 mL H2O)Source of chirality: hydrolysis of l-2cAbsolute configuration: (S)
(S)-2-Amino-2-(naphthalen-2-yl)ethanoic acid hydrochlorideC12H12NO2Cl[α]D20=-8.0 (19 mg/2 mL H2O)Source of chirality: hydrolysis of l-4cAbsolute configuration: (S)
