Ytterbium → 4-[2-Hydroxy-3-(2-methylbenzothiazol-5-yloxy)propyl]-piperazine-1-carboxylic acid tert-butyl ester

To a solution of 2-methyl-5-(oxiran-2-ylmethoxy)benzothiazole, a compound of formula (3) (6.2 g, 28 mmol), and tert-butyl 1-piperazinecarboxylate, a compound of formula (4) (5.7 g, 31 mmol), in methylene chloride (200 ml), was added ytterbium (111) trifluoromethanesulfonate (1.73, 28 mmol). The resulting solution was allowed to stir at room temperature overnight. The solvent was evaporated (in vacuo), to yield a semi-solid, which was chromatographed on silica gel, eluting with 5% methanol/methylene chloride, to yield 4-[2-hydroxy-3-(2-methylbenzothiazol-5-yloxy)propyl]-piperazine-1-carboxylic acid tert-butyl ester as a clear oil (9.5 g, 23 mmol).