6971-74-0Relevant articles and documents
Chemoselective Cleavage of Acylsulfonamides and Sulfonamides by Aluminum Halides
Sang, Dayong,Dong, Bingqian,Liu, Yunfeng,Tian, Juan
, p. 3586 - 3595 (2022/02/25)
The chemoselective cleavage of C-N bonds of amides, sulfonamides, and acylsulfonamides by aluminum halides is described. AlCl3and AlI3display complementary reactivities toward N-alkyl and N-acyl moieties. N-Alkylacylsulfonamides, sec
Controlled Relay Process to Access N-Centered Radicals for Catalyst-free Amidation of Aldehydes under Visible Light
Chang, Sukbok,Jeon, Hyun Ji,Jung, Hoimin,Kim, Dongwook,Lee, Wongyu,Seo, Sangwon
, p. 495 - 508 (2021/01/28)
Nitrogen-centered radicals have attracted increasing attention as a versatile reactive intermediate for diverse C–N bond constructions. Despite the significant advances achieved in this realm, the controllable formation of such species under catalyst-free conditions remains highly challenging. Here, we report a new relay process involving the slow in situ generation of a photoactive N-chloro species via C–N bond formation, which subsequently enables mild and selective access to N-centered radicals under visible light conditions. The utility of this approach is demonstrated by the conversion of aldehydes to amides, employing N-chloro-N-sodio carbamates as a practical amidating source. This synthetic operation obviates the need for catalysts, external oxidants, and coupling reagents that are typically required in related processes, consequently allowing high functional group tolerance and excellent applicability for late-stage functionalization. Amides are an important class of structural motifs prevalently found in bioactive compounds and synthetic materials of great significance. Amidation of aldehydes has been established as an atom-efficient strategy for amide synthesis; however, current methods lack in applicability mainly due to the requirement of troublesome reagents. In this article, we describe an unconventional relay process to convert aldehydes to amides under catalyst-, oxidant-, and coupling-reagent-free conditions, which is enabled by the development of a new mechanistic platform that gives efficient and controllable access to N-centered radicals under visible light. A wide range of (hetero)aromatic and aliphatic aldehydes can be employed, including those derived from biologically relevant complex molecules. We anticipate that the accomplished methodological advances, combined with the unique mechanistic features, will lead to the widespread application of the present strategy in broad research fields. A catalyst-free approach for controlled access to N-centered radicals is described, which enables the conversion of aldehydes to amides via an unconventional relay process harnessing visible light. The key tactic relies on the use of photostable N-chloro-N-sodio-carbamate amidating reagent that leads to slow incorporations of a photoactive radical source via C–N formation and other involved intermediates thereafter. This methodology displays excellent applicability and sustainable chemistry credentials and, thus, holds a promise for finding broad applications.
N-Aroylsulfonamide-Photofragmentation (ASAP)-A Versatile Route to Biaryls
Wessig, Pablo,Krebs, Saskia
supporting information, p. 6367 - 6374 (2021/09/29)
The photochemical fragmentation of N-aroylsulfonamides 9 (ASAP) is a powerful method for the preparation of various biaryls. Compounds 9 are easily accessible in two steps from amines by treatment with arenesulfonyl chlorides and aroyl chlorides. Many of these compounds were prepared for the first time. The irradiation takes place in a previously developed continuous-flow reactor using inexpensive UVB or UVC fluorescent lamps. Isocyanates and sulphur dioxide are formed as the only by-products. The ASAP tolerates a variety of functional groups and is even suited for the preparation of phenylnaphthalenes and terphenyls. The ASAP mechanism was elucidated by interaction of photophysical and quantum chemical (DFT) methods and revealed a spirocyclic biradical as key intermediate.
