Microwave-promoted rapid oxidation of toxic natural cisphenylpropenes (la-le) into high valued methoxylated benzaldehydes (2a-2e) was achieved within 2 min in high yield (71-84%) by reacting with sodium metaperiodate in the presence of catalytic amount of osmium tetraoxide (co-oxidant) and benzyltriethylammonium chloride (PTC).