(2S,5S)-2-Allyl-5-benzyloxymethyl-2-[4-(tert-butyl-diphenyl-silanyloxy)-butyl]-pyrrolidine

(2S,5S)-5-Benzyloxymethyl-2-(2-oxo-ethyl)-2-[4-(toluene-4-sulfonyloxy)-butyl]-pyrrolidine-1-carboxylic acid tert-butyl ester

(2S,5S)-2-Allyl-5-benzyloxymethyl-2-[4-(toluene-4-sulfonyloxy)-butyl]-pyrrolidine-1-carboxylic acid tert-butyl ester

(2S,5S,6R)-2-Benzyloxymethyl-6-non-2-ynoyl-1-aza-spiro[4.5]decane-1-carboxylic acid tert-butyl ester

(2S,5S,6R)-2-Benzyloxymethyl-6-(1-hydroxy-non-2-ynyl)-1-aza-spiro[4.5]decane-1-carboxylic acid tert-butyl ester