(S)-4-((2S,3R,5S,6R)-5-(benzyloxy)-3-((tert-butyldimethylsilyl)oxy)-6-methyltetrahydro-2H-pyran-2-yl)-1-((2R,3S,5R,6S)-5-(benzyloxy)-6-(2-(benzyloxy)ethyl)-3-hydroxy-3-methyltetrahydro-2H-pyran-2-yl)-3-hydroxybutan-2-one