N-methylmorpholine N-oxide (NMO) in conjunction with catalytic amounts of RuCl3 oxidizes unsaturated alcohols and primary alcohols selectively to the corresponding aldehydes. Kinetic studies indicate that the order with respect to NMO and catalyst is one. The order with respect to the substrate is variable, being zero at high concentrations and fractional at low concentrations. The proposed mechanism involves the rate-determining formation of an adduct between the alcohol and Ru(V). The activation parameters, determined under zero-order conditions with respect to the substrate, pertain to the formation of RuVO species from RuCl3 and NMO. © 1990.