1-Amino- and 1-Amidoalkyl Radicals: Generation and Stereoselective Reactions

Photoredox‐Initiated α‐Alkylation of Imines through a Three‐Component Radical/Cationic Reaction

“…[20b, 22e] Then, the reduced iridium species carries out a single electron transfer (SET) to activate the carbonbromine bond, forming the electron-deficient alkyl radical 5 and a bromide ion and regenerating the Ir 4 + catalyst. Enamide 1 then reacts with the electrophilic radical generated to give nucleophilic a-amido radical intermediate 6, [28] which can be rapidly oxidized to N-acyliminium cation 7, either by SET from Ir 4 + or by bromine atom transfer, and subsequently trapped by the ethanol component. [29] On the basis of previously proposed mechanisms, the radical propagation probably occurs through an atom-transfer mechanism.…”

Recent developments in cyclization reactions of α-aminoalkyl radicals

“…15a For synthetic applications, however, the obvious drawback with this strategy would be the need to dealkylate the cyclized product at some point in the synthetic scheme. Despite some of these shortcomings, a number of synthetic applications of neutral α-amino radicals have appeared over the years, 16 with the field of natural product synthesis being particularly well represented. 17 The excellent review by Renaud 16 covers the synthetic applications of α-acyl-and α-alkylamino radicals through 1995.…”

“…Despite some of these shortcomings, a number of synthetic applications of neutral α-amino radicals have appeared over the years, 16 with the field of natural product synthesis being particularly well represented. 17 The excellent review by Renaud 16 covers the synthetic applications of α-acyl-and α-alkylamino radicals through 1995. Picking up from that point, the present compilation focuses on recent applications of α-amino radicals in intramolecular processes mainly leading to nitrogen heterocycles.…”

Decarbonylative Radical Coupling of α‐Aminoacyl Tellurides: Single‐Step Preparation of γ‐Amino and α,β‐Diamino Acids and Rapid Synthesis of Gabapentin and Manzacidin A

“…[14] Eleven structurally distinct a-aminoacyl tellurides 1 a-k were prepared from readily available N-Boc-protected a-amino acids 6 a-k in a single step (Scheme 2). For instance, N-Boc-protected glycine 6 a was transformed into its activated ester by condensation with isobutyl chloroformate, and was then treated in situ with PhTeNa, which had been prepared from (PhTe) 2 and NaBH 4 , providing a-aminoacyl telluride 1 a. Tellurides 1 b-k were obtained in the same fashion, and all of the products were found to be stable to air, light, and silica gel. It is also noteworthy that Boc (1 a-k), TBS (1 c, e), and acetonide (1 k) groups were all tolerated under these conditions.…”

“…[1] a-Amino carbon radicals have served as useful species for the intermolecular construction of C À C bonds (Scheme 1). [2] In the context of coupling methods, N,X-acetals and a-amino acids have been typically used for the generation of a-amino carbon radicals. [3] Namely, radical formation and subsequent coupling were realized by homolytic cleavage of the CÀX bond of N,X-acetals (X = Br, [4] SePh, [5] SC(=S)OEt [6] ) or the decarboxylation of a-amino acids (Z = H [7] or N(C=S)R [8] ).…”