The process for removing a secondary hydroxyl group from an organic compound having at least one secondary hydroxyl group and having any amino groups protected, comprises the reaction of a reactive ester of said secondary hydroxyl group selected from the group consisting of an O-alkylthioester and an O-alkylselenoester with at least one mole of an organotin hydride, preferably tri-n-butylstannane, in an inert, aprotic solvent at a temperature of at least about 100.degree. C and under an inert atmosphere.The process is particularly useful in removing secondary alcohols in aminoglycoside antibiotics to produce deoxy derivatives thereof having antibacterial activity.Also described are novel O-sec.-alkylthiobenzoate, O-sec.-alkyl-S-methylxanthate, N-(sec.-alkoxythiocarbonyl)-imidazole esters, and di-O-alkylthiocarbonates having at least one secondary O-alkyl group, useful intermediates of the claimed process.