Dichloromethane → N-(tert-Butoxycarbonyl)-D-prolinal

Reaktionsgleichung

[OH:1][CH2:2][C@H:3]1[CH2:7][CH2:6][CH2:5][N:4]1[C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9].C(Cl)Cl.[Cr](Cl)([O-])(=O)=O.[NH+]1C=CC=CC=1>C(O)(=O)C>[CH3:14][C:11]([O:10][C:8]([N:4]1[CH2:5][CH2:6][CH2:7][C@@H:3]1[CH:2]=[O:1])=[O:9])([CH3:12])[CH3:13]

Komponenten

Versuchsvorschrift

In accordance with Scheme I, N-α-t-BOC-D-proline 2a is reacted in an ether solvent such as tetrahydrofuran at a temperature ranging from -2° C. to the reflux temperature of the solvent with 10M borane-methyl sulfide complex to produce (R)-2-(hydroxymethyl)-1pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester 3a. Compound 3a in a chlorinated hydrocarbon solvent such as methylene chloride is treated with an oxidizing agent such as pyridinium chlorochromate, 4Å molecular sieves and glacial acetic acid to give (R)-2-formyl-1-pyrrolidinecarboxylic acid 1,1-dimethylethyl ester 4a. Compound 4a in methylene chloride is treated with a methylene chloride solution of triphenylphosphine and carbon tetrabromide to produce (R)-2-(2,2-dibromoethenyl)-1pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester 5a. The dibromo compound 5a in an ether solvent such as tetrahydrofuran is reacted at -78° C. with an alkyl lithium reagent such as sec-butyllithium to give (R)-2-ethynyl-1-pyrrolidinecarboxylic acid, 1,1-dimethylethyl ester 6a.