The Cu-catalyzed C-H activation of alkanes in the presence of O-methyl-N-nitroisourea affords a facile entry to O-methyl-N-alkylnitroisoureas, shelf stable and benign isocyanate precursors. The latter is then readily converted into carbamates and ureas via an uncommon chloride-mediated demethylation process. O-methyl-N-nitroisourea is available in two steps and large-scale from urea and constitutes an easy to handle NCO surrogate. The methodology has also been applied to the synthesis of a methylisocyanate (MIC) precursor, a valuable synthon for pharmaceutical and agrochemical purposes and for the post-functionalization of a low density polyethylene.
Experimental procedures, 1H and 13C NMR, FT-IR and HRMS for all new compounds, X-ray data. GC-MS and 1H NMR for mechanistic studies