Visible-light activated metal catalyst-free vicinal diazidation of olefins with sulfonium iodate(i) species

Abstract

An unprecedented visible-light inspired selective radical azidation of unactivated and diverse substituted vinylarenes with sulfonium iodate reagent has been realized. The intrinsic radical process triggered by light tolerated several synthetically useful functionalities enabling two new carbon-hetero bonds which display distinctive late-stage applications to biologically relevant scaffolds.

Catalytic Azido‐Hydrazination of Alkenes Enabled by Visible Light: Mechanistic Studies and Synthetic Applications

“…Since the azo‐ene reaction is a potential competing pathway, we deliberately selected but‐3‐en‐1‐yl benzoate ( 1 a ) that possesses allylic C−H bonds as a model substrate for the catalyst discovery and condition optimization. Current methods that convert TMSN 3 to azide radicals under visible light require sophisticated photocatalysts such as Ir‐complexes, acridinium salts, Rose Bengal and sulfonium iodate . Following our recent discoveries, simple ketone photo‐sensitizers were first attempted to generate azide radical due to their availability.…”

“…These preliminary results encouraged us to develop this sequential radical addition mode into a more synthetically useful protocol. [27,28] [19] Also, azide is a versatile functional group that serves an excellent linker, [20] a reliable nitrene precursor [21] and many other roles.…”

“…[22] Azide anion and its equivalents are well-known to be converted to azide radicals by multiple types of oxidants like redox-active transition metals, [23] hyper-valent iodines, [24] peroxide, [25] electrochemical mediators, [26] and photosensitizers. [27,28]…”

Vicinal difunctionalization of carbon–carbon double bond for the platform synthesis of trifluoroalkyl amines

“…Naphthalene substituted dimethylamine afforded diamine 19 in an excellent 90% yield. Increasing the steric bulk of the amine, reactions with diisobutylamine and dibenzylamine led to 67% yields of products (20,21). In contrast to the aromatic systems, the presence of an electron withdrawing ester group on the alkyl chain was well tolerated and iminodiacetic acid ester provided diamine 22 in almost quantitative yield.…”

“…1c) 1,5 . Indeed, a diverse set of methodologies have been developed to introduce nitrogen atoms attached the same substituents onto carbon-carbon double bond, i.e., diazidation and homodiamination reactions in metal-assisted 6,7 , metal-catalyzed [8][9][10][11][12][13] , organoselenium-catalyzed 14 , hypervalent iodine-assisted and -catalyzed [15][16][17][18][19] photochemical [20][21][22][23] and electrochemical 24,25 fashions.…”