A Ligand Containing Five Nitrogen Atoms Enabled Efficient Homocyclization of α-Bromocarbonyl Amides in the Presence of a Copper Catalyst

The synthesis of iminolactone is one of the most difficult areas in organic chemistry. In this research, we found efficient control of generation of a radical and acrylamide from α-bromoamide enabled an iminolactonization reaction in the presence of a copper catalyst. The use of a ligand that possesses five nitrogen atoms allowed for this homocyclization, giving facile access to various functionalized iminolactones in good yields. Iminolactonization of α-bromoamide has been developed. The key to success of this reaction is generation of alkyl radical and acrylamide by reaction of α-bromoamide with copper and ligand L8 containing five nitrogen atoms.