Stereospecific Assembly of Fused Imidazolidines via Tandem Ring Opening/Oxidative Amination of Aziridines with Cyclic Secondary Amines Using Photoredox Catalysis

Abstract

Sustainable assembly of imidazolidines is accomplished via a sequential stereospecific ring opening and C–H amination using aziridines with secondary cyclic amines under visible light mediated indazoloquinoline photoredox catalysis at ambient conditions. Optically active aziridines are coupled with high enantiomeric purities. The computational studies provide insights on the redox properties of the catalysts as well as a profile of the reaction.

Oxidative C–H/C–H Annulation of Imidazopyridines and Indazoles through Rhodium-Catalyzed Vinylene Transfer

“…Upon our continuous research interest in this area, we envisioned utilizing this reaction system as an unprecedented π-extension method via the C–H/C–H oxidative vinylene cyclization. To test the feasibility, we chose imidazole- and pyrazole-fused aromatics as representative substrates, whose enriched nucleophilicity of the C3 positions would facilitate the carbocyclization. , Considering the potential application of the corresponding coupling products in biologically active compounds (such as rifaximin derivatives), fluorescence materials, , photoredox catalysis, etc., the development of a new vinylene annulation protocol would attract considerable attention. In this manuscript, we report a direct assembly of polyaromatic scaffolds by the Rh-catalyzed annulative coupling of imidazopyridine and indazole derivatives with vinylene carbonate (Scheme b).…”

Synthesis of Imidazo[2,3‐a]isoquinoline and Imidazo[3,2‐a]quinoline Derivatives with Ynones, Isoquinolines and Quinolines

“…Seidel et al have devised a convenient redox‐annulation approach for synthetic route to imidazolidinone derivatives with α‐ketoamides and tetrahydroisoquinolines under the catalysis of benzoic acid [8] . The Punniyamurthy's group has also reached an asymmetric synthesis of tetrahydroimidazo[2,3‐ a ]isoquinolines with aziridines and tetrahydroisoquinolines under visible light mediated indazoloquinoline photoredox catalysis through a sequential stereospecific ring opening and C−H amination sequence [9] …”

“…Beside of extensive study by Cronin and co-workers on the construction of dihydro-imidazo-phenathridiniums, imidazophenathridiniums and related molecules by multistep synthesis, [2] a range of elegant methods have been developed for the synthesis of imidazo[2,3-a]isoquinoline and imidazo[3,2a]quinoline derivatives in the past two decades (Scheme 1). [3][4][5][6][7][8][9][10][11][12] As an intramolecular case, Punniyamurthy et al have developed a simple method for the preparation of tetrahydroimidazo[2,3a]isoquinolines through on water C(sp 3 )-H functionalization/ CÀ O/CÀ N bond formation employing TBAI as a catalyst (eq 1). [3] Intermolecular reactions for the preparation of imidazo[2,3a]isoquinolines always rely on direct modification of isoquinolines and their derivatives.…”

“…[8] The Punniyamurthy's group has also reached an asymmetric synthesis of tetrahydroimidazo[2,3-a]isoquinolines with aziridines and tetrahydroisoquinolines under visible light mediated indazoloquinoline photoredox catalysis through a sequential stereospecific ring opening and CÀ H amination sequence. [9] However, the synthesis of imidazoquinolines is a much less explored research field. There are only two reported strategies for the general synthesis of imidazoquinolines.…”

Thiocarbamoyl Fluoride Synthesis by Deconstructive Diversification of Arylated Tetrahydroisoquinolines

“…As shown in Scheme , the photoexcited photocatalyst abstracts an electron from a tertiary amine ( 1 ). Hydrogen atom abstraction occurs to form the iminium ion 6 , which can react with a variety of nucleophiles. , In the presence of a trace amount of water, hydroxy compound 7 is formed from 6 . There are two possible transformations of 7 .…”