titanium(IV) isopropylate; 2-hydroperoxy-2-methyl-1-propanol; 4 A molecular sieve T=20°C; 1 h; other reagents: 2,3-dimethyl-3-hydroperoxy-2-butanol, 2-hydroperoxy-2-phenyl-1-ethanol, m-chloroperoxybenzoic acid, NaHCO3, dimethyldioxirane;