Study On 1,2-Azide And 1,4-Oxygen Migration Of Vinyl Azides

Vinyl azide is an important "family member" in the azide family.It has drawn great attention in organic synthesis,medicinal chemistry and materials science.Because of the unique structure of vinyl azide-including both the azide group of the electron donor and the olefin structure,it has an increasingly broad research prospect.In the hundred years since the discovery of vinyl azide,due to its potential dangers and immature synthetic methods,the application research of vinyl azide has been slow and difficult to develop for a long time.With the continuous improvement of vinyl azide synthesis methods,more and more safe and efficient synthesis methods have been reported,and the application research of vinyl azide has been developing more and more rapidly.Vinyl azide applications include conversion to amines,Staudinger ligation,synthesis of phosphazenes for aza-Wittig reactions,and as precursors of nitriles.It is also widely used as the 1,3-dipole of alkynes in cycloaddition reactions.Among them,vinyl azide can be used as a nucleophile,an electrophile,a free radical acceptor and the like.In the study of the development of vinyl azides,migration of azide groups from readily available azide precursors may be one of the most attractive methods because this method not only has high atomic economy and step economy Moreover,it can provide azide compounds which are difficult to synthesize by other conventional methods.However,because this group is easily decomposed during the migration process,leading to the release of nitrogen molecules,the development of the azide migration reaction is still a difficult challenge.Therefore,the azide migration reaction is very rare.In this paper,we show a novel neighbouring carbonyl group-assisted sequential1,2-azide and 1,4-oxygen migration reaction of vinyl azides for the efficient preparation of a range of ?-azido ketones.This represents the first transformation of vinyl azides into ?-azido ketones.Notable features of this method are its high efficiency,broad substrate scope,excellent functional group compatibility,and high yields.The computational studies gave a key insights into the regioselective 1,2-azide and 1,4-oxygen migrations assisted by the neighbouring carbonyl group.Further conversions into a variety of nitrogen-containing compounds demonstrated the synthetic utility of the ?-azido ketone products.Preliminary mechanistic studies disclosed a novel reaction mechanism involving neighbouring carbonyl group-assisted sequential 1,2-azide and 1,4-oxygen migrations.