(S)-2-[(4R,5S,6S)-2,2-Di-tert-butyl-5-methyl-6-((S)-1-methyl-2-oxo-butyl)-[1,3,2]dioxasilinan-4-yl]-propionaldehyde

(S)-2-[(4R,5R,6R)-2,2-Di-tert-butyl-6-((1R,2S)-2-hydroxy-1-methyl-butyl)-5-methyl-[1,3,2]dioxasilinan-4-yl]-propionaldehyde