The invention relates to a process for transformation of lignocellulosic biomass or cellulose using in a simultaneous manner an original combination of at least two homogeneous catalysts and one or more heterogeneous catalyst(s). The use of these catalysts makes it possible to obtain mono-oxidized or poly-oxidized upgradable products directly and to limit the formation of non-upgradable products. Non-upgradable products are defined as soluble and non-soluble humins, i.e., products of high molecular weight obtained from undesirable condensation reactions of sugars and their derivatives.