1309041-51-7Relevant articles and documents
DBU-promoted nucleophilic activation of carbonic acid diesters
Carafa, Marianna,Mesto, Ernesto,Quaranta, Eugenio
, p. 2458 - 2465 (2011)
The reactivity of carbonic acid diesters in the presence of the amidine base DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) has been investigated for the first time. Organic carbonates can be activated by DBU through the formation of N-alkoxycarbonyl ketene aminal 2 as the ultimate product. The latter species may form through deprotonation of the corresponding N-alkoxycarbonyl-amidinium cation 1+ by the amidine base. We have for the first time isolated and characterized, both in the solid state (X-ray crystal structure determination, IR) and in solution (NMR), a few 1+ chloride salts and studied their reactivity towards the organic base. The reactivity of both 1+ and 2 with methanol has also been explored. Ketene aminal 2 behaves as a "CO2R" carrier, as it can selectively transfer the alkoxycarbonyl group to the alcohol and regenerate the amidine base. Carbonic acid diesters can be activated by the amidine base DBU to give N-alkoxycarbonyl ketene aminal 2. The latter species may form through deprotonation of N-alkoxycarbonyl-amidinium cations 1+ by the amidine base and behave as carriers of the -C(O)OR group. Copyright
