[(R)-Cyano-((4S,5R)-2,2,4,5-tetramethyl-[1,3]dioxolan-4-yl)-methyl]-carbamic acid tert-butyl ester

2-((1S,2S,3R)-1-Amino-2,3-dihydroxy-2-methyl-butyl)-thiazole-4-carboxylic acid ethyl ester

2-[(S)-tert-Butoxycarbonylamino-((4S,5R)-2,2,4,5-tetramethyl-[1,3]dioxolan-4-yl)-methyl]-thiazole-4-carboxylic acid ethyl ester

2-[(S)-[tert-Butoxycarbonyl-(2,2,2-trifluoro-acetyl)-amino]-((4S,5R)-2,2,4,5-tetramethyl-[1,3]dioxolan-4-yl)-methyl]-thiazole-4-carboxylic acid ethyl ester