The present invention is directed to processes for producing isocyanates and isocyanate derivatives from epoxide and carbon monoxide reagents. In preferred embodiments, the processes include a step for providing carbonylation of an epoxide reagent with a carbon monoxide reagent to produce a beta-lactone intermediate. In certain preferred embodiments, further carbonylation of a beta-lactone intermediate produces a succinic anhydride intermediate. The processes of the present invention include steps for rearranging beta-lactone intermediates and/or succinic anhydride intermediates to produce isocyanate products and/or isocyanate derivatives. In certain preferred embodiments, the isocyanate products may be copolymerized with polyol oligomers to provide polyurethane products.