TEMPO and its derivatives mediated reactions under transition-metal-free conditions

In this review, 2, 2, 6, 6-tetramethyl-1-piperidinyl-N-oxyl (TEMPO) and its derivatives as stable radicals can act not only as the substrates to capture or initiate new radical intermediates, but also as organic catalysts or oxidants for transformations of alkenes, alcohols, aldehydes and so on to provide various high value-added compounds in the absence of transition metals.