Generation and Trapping of Nitrosocarbonyl Intermediates

The nitrosocarbonyls (R−CONO) are highly reactive species and
remarkable intermediates toward different synthetic targets. This review will cover a
research area whose impact in current organic synthesis is constantly increasing in the
chemical community. This review represents the first and comprehensive picture on the
generation and trapping of nitrosocarbonyls and is solidly built on more than 380
papers. Six different classes of key starting materials such as hydroxamic acids, Nhydroxy
carbamates, N-hydroxyureas, nitrile oxides, and 1,2,4-oxadiazole-4-oxides were
highlighted. The content of the review surveys all the methods to generate the
nitrosocarbonyls through different approaches (oxidative, thermal, photochemical,
catalytic, aerobic, and the less common ones) in the light of efficiency, yields, and
mildness. The most successful trapping agents employed to catch these fleeting
intermediates are reviewed, exploiting their superior dienophilic, enophilic, and electrophilic power. The work is completed by
paragraphs dedicated to the detection of the intermediates, theoretical studies, and insights about the challenges and future
directions for the field.