Hydrazine sulphate: a cheap and efficient catalyst for the regioselective ring-opening of epoxides. A metal-free procedure for the preparation of β-alkoxy alcohols

An efficient and general procedure for the regioselective ring opening of epoxides with alcohols to afford the corresponding β-alkoxy alcohols, using hydrazine sulphate as catalyst, is described. This new metal-free process was found to be highly versatile allowing the use of primary, secondary and tertiary alcohols as nucleophiles and a large variety of epoxides, including 5α,6α-, 5β,6β- and 2α,3α-epoxysteroids, as substrates.