Iridium-catalyzed Green Synthesis Of N-alkyl Ureas,3,3’-BIMs And Amides

Transition metal iridium-catalyzed using alcohols as alkylation agents to form C-N and C-C bonds to synthesis N-alkyl ureas,3,3’-BIMs, which uses cheap and less t-oxic alcohol instead of the high poisonous halogenated hydrocarbon as electrophilic r-eagent to accomplish alkylation reaction, and has highly atom efficiency and the for-mation of water as the side product, according with the demand of green chemistry, and therefore has a certain development prospect. At the same time, the use of water-soluble iridium complexes catalyze the rearrangement oximes to amides under mild c-onditions in the water, which has a certain practical value.This thesis mainly includes three aspects, using iridium complexes as the main line to synthetize N-alkyl ureas,3,3’-BIMs and amides.1. The protocol for the synthesis of N,N’-alkylarylureas and N,N’-dialkylureas via transition metal-catalyzed regioselective N3-alkylation of the N-substituted urea with alcohols was proposed and accomplished in the presence of iridium/NaOH system. From both synthetic and environmental points of view, the reaction is highly attractive because of easily available starting materials, high atom efficiency and the formation of water as only side product. Notably, the novel strategy for the development of regioselective N-alkylation with alcohols would facilitate the progress of "hydrogen auto-transfer" process.2. We demonstrated the direct coupling of indoles with methanol to3,3’-BIMs with good to excellent yields using the commercially available iridium complex. Significantly, the research exhibited the potential of direct use of abundant and renewable methanol as the alternative of highly poisonous formaldehyde for synthetic transformation and the low catalyst loading (0.2mol%[Cp*IrCl2]2), which saves the cost of the reaction and has a certain application value.3. In the presence of water-soluble iridium complex [Cp*Ir(H2O)3][OTf]2, a variety of aldoximes, including aromatic, aliphatic, conjugated unsaturated and non-conjugated unsaturated aldoximes, were converted into the corresponding amides in water with good to excellent yields. Further, the one-pot synthesis of amides from aldehydes, hydroxylamine hydrochloride and sodium carbonate via a tandem condensation/rearrangement reaction in water was also accomplished. The present catalyst exhibited some advantages such as phosphorus ligand-free, low catalyst loading, and operational convenience under air atmosphere.