The protection of the OH group of 2-hydroxyacetonitrile (I) with TBDMS-Cl and imidazole in THF gives the silyl ether (II), which is treated with pentylmagnesium bromide (III) in ethyl ether yielding the protected 1-hydroxyoctan-3-one (IV), which is deprotected with HCl in methanol/water affording the corresponding hydroxyketone (V). Finally, this compound is treated with hydroxylamine-O-sulfonic acid in liquid ammonia.