Studies On Iridium Catalyzed C-N Bond Formation Using Organic Azides As Nitrogen Source And Internal Oxidant

Recently,the direct C-H bond functionalization have been developed as more facility,straightforward and atom-economic protocols to construct C-N bonds.However,most of transition-metal-catalyzed C-H amination reactions require stoichiometric external oxidants and the harsh reaction conditions.Organic azides have been developed as an amino source and internal oxidant by N-N2 bond cleavage,providing environmentally benign methods for the direct C-H amination without external oxidants.This thesis mainly focuse on the development of iridium-catalyzed direct C-H amination reactions starting from organic azides.The main results obtained are as follows:1.Controlling of site selectivity is one of the challenges in C-H bonds activation.Various of directing groups have successfully been developed.Aldehyde as an efficient directing group remains challenging,due to its low ligating ability of the aldehyde oxygen and related competitive side reactions.In addition,aldimine offers stronger chelation assistance for C-H activation and act as a mask of aldehydes.Therefore,we have developed an iridium-catalyzed direct C-H amidation of N-Ts imines as a removable directing group with sulfonyl azides,in which C-H amidation and hydrolysis were involved in one pot manner.A series of ortho-amided benzaldehydes were obtained in up to 95% yields.This transformation could proceed smoothly with low catalyst loading without external oxidants,acids,or bases.Molecular nitrogen was released as the sole byproduct,providing an environmentally benign sulfamidation process.2.Organic azides have been developed as an amino source and internal oxidant by N-N2 bond cleavage,providing methods for the direct C-H amination.Although substantial achievements have been made.Howeverthe poor selectivity between mono-and diamidation remains a large challenge.One of the two ortho positions of the arene needs to be blocked to overcome the problem,which is the major limitation for this synthetic application.Thus,there is still great room for the development ofnew directing groups with unique character,especially for thet unable ability to achieve a regioselective monoamidation by C–H activation.Herein,we have disclosed an Ir-catalyzed selective mono-and diamination of quinazolinone with single directing with sulfonyl azides as amino sources.Using quinazolinone as the directing functional groups,highly selective mono-or diaminationwas achieved in a reaction.This procedure could be proceeded smoothly with low catalyst loading and tolerant various substituent groups.