A one-pot cascade transformation of chalcones into beta-imidoketones has been developed, in which NBS provides both electrophilic bromine and nucleophilic nitrogen sources, and DBU functions as a nucleophilic reagent to activate NBS to be a more electrophilic bromine species and to further remove the bromine of alpha-bromoketones. The whole process involves tandem bromoamination and debromination, which represents a unique example of preparing beta-aminoketones by the reaction of chalcones with the NBS/DBU combination.
CBr<sub>4</sub> as a Halogen Bond Donor Catalyst for the Selective Activation of Benzaldehydes to Synthesize α,β-Unsaturated Ketones
作者:Imran Kazi、Somraj Guha、Govindasamy Sekar
DOI:10.1021/acs.orglett.7b00348
日期:2017.3.3
CBr4 has been employed as a halogen bond donor catalyst for the selective activation of aldehyde, to achieve an efficient solvent- and metal-free C═C bond forming reaction in the presence of strong acid sensitive groups such as methoxy, cyanide, ester, and ketal for the synthesis of α,β-unsaturated ketones. This unique capability of CBr4 to act as a halogen bond donor has been explored and established