Unprecedented formation of Δ2-isoxazoline and/or 1-nitroso-pyrazoline from α-bromoketone oximes and diazo compounds

Reaction of α-bromoketone oximes with diazo compounds in the presence of a metal catalyst and base led to the unprecedented formation of two types of rings: Δ 2 -isoxazolines and 1-nitrosopyrazolines.