Toluene-4-sulfonic acid 4-{(4S,5S)-5-[(S)-1-(tert-butyl-dimethyl-silanyloxy)-but-2-ynyl]-2-oxo-oxazolidin-4-yl}-but-3-ynyl ester

Toluene-4-sulfonic acid 3-[(3aS,6S,6aS)-6-(tert-butyl-dimethyl-silanyloxy)-5-eth-(Z)-ylidene-2-oxo-hexahydro-cyclopentaoxazol-(4Z)-ylidene]-propyl ester

(2aS,3S,7bS)-3-(tert-Butyl-dimethyl-silanyloxy)-4-eth-(Z)-ylidene-2a,3,4,6,7,7b-hexahydro-2-oxa-7a-aza-cyclopenta[cd]inden-1-one