5-Benzofuranmethanol, 3-[2-[[(1,1-dimethylethyl)dimethylsilyl]oxy]ethyl]-2,3-dihydro-4,6-bis(meth oxymethoxy)-2-[[tris(1-methylethyl)silyl]oxy]-a-[2,4,6-tris(phenylmethoxy) phenyl]-