Use of N,N'-dimethoxy-N,N'-dimethylurea as a carbonyl dication equivalent in organometallic addition reactions. Synthesis of unsymmetrical ketones

We report the synthesis of N,N'-dimethoxy-N,N'-dimethylurea (4) and its use as a carbonyl dication equivalent. This reagent was also independently developed by Hlasta and Court. The urea 4 was formed in 78% yield from the addition of a solution of bis (trichloromethyl) carbonate (triphosgene) in THF to N-methoxy-N-methylamine. (Trichloromethyl) chloroformate (diphosgene) also works well