Carbamic acid, N,N-dimethyl-,(1R,2R,3R,4S,5R)-1-[(1S,3E)-1-(acetyloxy)-4-methyl-3,5-hexadien-1-yl]-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-5-methyl-2-(1-methylethenyl)-8-oxo-6-oxabicyclo[3.2.1]oct-4-yl ester