Linear alpha,omega-epoxyaldehydes with variable distance between the two functional groups, a class of interesting cross-linking agents for proteins, polysacharides and other polymeric compounds, can be conveniently prepared by hydroformylation of commercially available alpha,omega-epoxyalkenes catalyzed by rhodium/phosphine complexes. For example, 1,2-epoxyhex-5-ene (2b) was converted into 6,7-epoxyheptanal (1b) with 75-99% yields in the presence of the catalytic system HRh(CO)(PPh3)(3)/xantphos at 20 atm (CO/H-2 = 1) and at 40-100 degreesC. Operating at 40 degreesC practically regiospecific formation of the linear epoxyaldehyde was found. (C) 2002 Elsevier Science B.V. All rights reserved.