(S)-3-(2,2-Dimethoxy-ethyl)-4-methyl-pentanoic acid methyl ester

(4S,6S)-6-{(S)-1-[(3S,5S,8R,9S,10S,13S,14S)-3-(tert-Butyl-diphenyl-silanyloxy)-10,13-dimethyl-2,3,4,5,6,7,8,9,10,11,12,13,14,15-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]-ethyl}-4-isopropyl-tetrahydro-pyran-2-one