Recent Advances in Gold-Catalyzed N- and O-Functionalizations of Alkynes with Nitrones, Nitroso, Nitro and Nitroxy Species

Nitrone and nitroso species are versatile compounds to react with alkenes or butadienes to access five- and six-membered nitroxy (NO) containing heterocycles, to offer further access to acyclic 1,3- and 1,4-amino alcohols after facile cleavage of the NO bonds. The N- and O-functionalizations of alkynes with nitrones or nitroso species have been explored less well than the corresponding alkene reactions. In recent decades, gold catalysts have enabled the electrophilic activation of alkynes with weak nucleophiles. This review summarizes recent progress to implement N- and O-functionalizations of alkynes with common NO containing species including nitrone, nitroso, nitro and other nitroxy derivatives. Reported reactions include the following three topics: (i) 1,2-difunctionalizations, (ii) cyclizations and (iii) cycloaddition or annulation reactions. The review is organized according to the types of nucleophiles, followed by reactions of the mentioned types. Enantioselective functionalizations of alkynes with these nitroxy nucleophiles are also included.