(R)-10-((4R,6R)-2,2,6-Trimethyl-[1,3]dioxan-4-ylmethyl)-9-oxa-1,5-dithia-spiro[5.5]undecan-8-one

(R)-10-[(R)-2-(tert-Butyl-diphenyl-silanyloxy)-propyl]-9-oxa-1,5-dithia-spiro[5.5]undecan-8-one

{(2R,4R,6S)-6-[(R)-2-(tert-Butyl-diphenyl-silanyloxy)-propyl]-4-hydroxy-2-methoxy-tetrahydro-pyran-2-yl}-acetic acid tert-butyl ester

{(2R,6R)-6-[(R)-2-(tert-Butyl-diphenyl-silanyloxy)-propyl]-2-methoxy-4-oxo-tetrahydro-pyran-2-yl}-acetic acid tert-butyl ester