Herein we describe a compelling sequential methodology for obtaining optically active α‐arylmethanols‐1,2,3‐triazoles. The approach is based on the enantioselective alkynylation of aldehydes followed by a one‐pot two‐step desilylation/CuI‐catalyzed azide‐alkyne 1,3‐dipolar cycloaddition (CuAAC), providing the corresponding products with excellent yields and high levels of enantioselectivity. Furthermore, the click chemistry can be performed without affecting the enantiomeric excess. The application of the reaction has been demonstrated in the synthesis of a 1,2,3‐triazole analog of antihistaminic and anticholinergic drug (R)‐orphenadrine.
Sulfones and carboxylic acids are prominent motifs widely present in the chemical structure of agrochemicals, pharmaceuticals and many other highly valuable compounds. Herein, we describe a conjunctive strategy for the precise installation of these functionalities onto styrenes using sodium sulfinates and CO 2 as coupling partners. The protocol allowed the preparation of carboxy-sulfonylated compounds in good yields and broad functional group tolerance. Additionally, taking advantage of the leaving group ability of the sulfone moiety, a one-pot photocatalytic carboxy-sulfonylation-elimination strategy was developed for the synthesis of α-aryl-acrylates.
The Front Cover shows a chiral arylmethanols bearing the 1,2,3‐triazole moiety, with a variety of di(hetero)arylmethanols, which do not contain any N‐heteroatom. Such molecules can be obtained by using a straightforward sequential approach based on the enantioselective alkynylation of aldehydes followed by a one‐pot two‐step desilylation/CuAAC, providing the products with excellent yields and high levels of enantioselectivity. More information can be found in the https://doi.org/10.1002/ejoc.201800751
RECENT APPLICATIONS OF THE ORGANIC PHOTOCATALYST 1,2,3,5-TETRAKIS(CARBAZOL-9-YL)- 4,6-DICIANOBENZENE IN CHEMICAL TRANSFORMATIONS. Ruthenium and iridium polypyridine complexes are among the most employed photocatalysts described in literature. The broad applicability is due to the redox potentials and long half-life times of the excited state which these molecules presented. The pursuit for metal-free alternatives has been intensified in the last few years, therefore, many organic fluorophores were successfully employed as photocatalysts. Among them, 1,2,3,5-tetrakis(carbazol-9-yl)- 4,6-dicianobenzene (4CzIPN) recently drawn attention of the community, and it’s been widely employed by distinguished research groups. Recent studies have shown that this catalyst do not only present similar properties to transition metal complexes, but also, its synthesis can be accomplished more easily and less expensive when compared with the metallic photocatalysts above mentioned. Therefore, 4CzIPN constitutes a metal-free alternative to replace transition metal complexes in conventional photochemical protocols. Moreover, it’s as a powerful ally in the development of new photochemical approaches. In this work, we aim to summarize recent applications of 4CzIPN as catalyst in the emerging field of redox photocatalysis.
A dual photocatalytic sulfonylation-arylation of electron-rich alkenes is described. By combining sulfinate salts, (hetero)-arylbromides and 2,3-dihydrofuran under Ru and Ni dual catalysis, over 35 examples of aryl-sulfonylated scaffolds could be obtained in good to excellent yields, under mild reaction conditions and high diastereoselectivity.
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