4-tert-Butoxycarbonylamino-2,2-difluoro-butyric acid

3-(Carboxy-difluoro-methyl)-3-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester Cyclobutyl-difluoro-acetic acid 3-(Carboxy-difluoro-methyl)-pyrrolidine-1-carboxylic acid tert-butyl ester Cyclopentyl-difluoroacetic acid 3-(Carboxy-difluoro-methyl)-3-hydroxy-azetidine-1-carboxylic acid tert-butyl ester 4-(Carboxy-difluoro-methyl)-4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester 3-(Carboxy-difluoro-methyl)-azetidine-1-carboxylic acid tert-butyl ester 3-(Carboxy-difluoro-methyl)-piperidine-1-carboxylic acid tert-butyl ester Difluoro-(tetrahydro-furan-3-yl)-acetic acid