(R)-N-Boc-2,2-dimethyl-4-ethynyloxazolidine

(R)-2,2-Dimethyl-3-(N-Boc)-4-ethynyl-oxazolidine

(4R)-3-(tert-Butoxycarbonyl)-4-ethynyl-2,2-dimethyloxazolidine

(4R)-4-Ethynyl-2,2-dimethyl-3-oxazolidinecarboxylic acid 1,1-dimethylethyl ester