(2R,3S)-3-(tert-Butyl-dimethyl-silanyloxy)-4-[(2S,3S,4S,5S,6R,9S,11S)-4-(tert-butyl-dimethyl-silanyloxy)-9-ethyl-3,5,11-trimethyl-8-oxo-1-oxa-7-aza-spiro[5.5]undec-2-yl]-2-methyl-butyraldehyde

(2S,3R,4S,5S,6R,9S,11S)-2-((2S,3S)-7-Bromo-2-hydroxy-3-methyl-hept-6-ynyl)-9-ethyl-4-hydroxy-3,5,11-trimethyl-1-oxa-7-aza-spiro[5.5]undecan-8-one

(2S,3S,4S,5S,6R,9S,11S)-4-(tert-Butyl-dimethyl-silanyloxy)-2-[(2S,3S)-2-(tert-butyl-dimethyl-silanyloxy)-3-methyl-pent-4-enyl]-9-ethyl-3,5,11-trimethyl-1-oxa-7-aza-spiro[5.5]undecan-8-one

(2S,3S,4S,5S,6R,9S,11S)-4-(tert-Butyl-dimethyl-silanyloxy)-2-[(2S,3S)-2-(tert-butyl-dimethyl-silanyloxy)-3-methyl-hept-6-ynyl]-9-ethyl-3,5,11-trimethyl-1-oxa-7-aza-spiro[5.5]undecan-8-one