New Aspects of Catalytic Intramolecular C-H Amination: Unexpected Formation of a Seven-membered Ring in Nitrogen-containing Systems

The first example of the formation of a seven-membered ring by way of intramolecular-catalyzed amination of saturated C-H bonds is reported (Du Bois reaction). The influence of various structural parameters was studied, and it was shown that the unexpected regioselectivity observed in nitrogen-containing systems could be rationalized by conformational factors. These results open the way to innovative strategies for the general synthesis of polyfunctionalized piperidines.