Chloro/bromotrimethylsilane-Cu(NO3)2·3H2O: Safe and efficient reagent system for the decarboxylative ipso-nitration and dibromination of cinnamic acids

•A safe and convenient decarboxylative nitration method for cinnamic acids.•Chlorotrimethylsilane-Cu(NO3)2·3H2O is an efficient nitrating system.•Decarboxylative nitration is stereoselective.•Bromotrimethylsilane-Cu(NO3)2·3H2O is an efficient brominating system.•The nitration and bromination methods are versatile for a variety of cinnamic acids.