131196-45-7Relevant articles and documents
Reactions of 2,2,6-Trimethyl-1,3-dioxin-4-one with the Aryl Aldimines Prepared from Thiophene-2-carbaldehyde
Koser, ?layda,Ocal, Nuket,Erden, Ihsan
, p. 1828 - 1832 (2017)
The reactions of aryl aldimines derived from thiophene-2-carbaldehyde (5–9) with 2,2,6-trimethyl-1,3-dioxin-4-one (1) were investigated. The new 1,3-oxazin-4-ones and thienylidene acetoacetamides were obtained in good yields. The synthetic utility of the latter via an intramolecular tandem Friedel–Crafts alkylation–acylation to give tetracyclic heterocyclic rings was also explored.
A new catalytic approach for aerobic oxidation of primary alcohols based on a Copper(I)-thiophene carbaldimines
Lagerspets, Emi,Valbonetti, Evelyn,Eronen, Aleksi,Repo, Timo
, (2021/06/03)
We report here novel Cu(I) thiophene carbaldimine catalysts for the selective aerobic oxidation of primary alcohols to their corresponding aldehydes and various diols to lactones or lactols. In the presence of the in situ generated Cu(I) species, a persistent radical (2,2,6,6-tetramethylpiperdine-N-oxyl (TEMPO)) and N-methylimidazole (NMI) as an auxiliary ligand, the reaction proceeds under aerobic conditions and at ambient temperature. Especially the catalytic system of 1-(thiophen-2-yl)-N-(4-(trifluoromethoxy)phenyl)methanimine (ligand L2) with copper(I)-iodide showed high reactivity for all kind of alcohols (benzylic, allylic and aliphatic). In the case of benzyl alcohol even 2.5 mol% of copper loading gave quantitative yield. Beside high activity under aerobic conditions, the catalysts ability to oxidize 1,5-pentadiol to the corresponding lactol (86% in 4 h) and N-phenyldiethanolamine to the corresponding morpholine derivate lactol (86% in 24 h) is particularly noteworthy.
Enantioselective Reductive Cyanation and Phosphonylation of Secondary Amides by Iridium and Chiral Thiourea Sequential Catalysis
Chen, Dong-Huang,Sun, Wei-Ting,Zhu, Cheng-Jie,Lu, Guang-Sheng,Wu, Dong-Ping,Wang, Ai-E,Huang, Pei-Qiang
supporting information, p. 8827 - 8831 (2021/03/16)
The combination of transition-metal catalysis and organocatalysis increasingly offers chemists opportunities to realize diverse unprecedented chemical transformations. By combining iridium with chiral thiourea catalysis, direct enantioselective reductive cyanation and phosphonylation of secondary amides have been accomplished for the first time for the synthesis of enantioenriched chiral α-aminonitriles and α-aminophosphonates. The protocol is highly efficient and enantioselective, providing a novel route to the synthesis of optically active α-functionalized amines from the simple, readily available feedstocks. In addition, the reactions are scalable and the thiourea catalyst can be recycled and reused.
Air-Stable Half-Sandwich Iridium Complexes as Aerobic Oxidation Catalysts for Imine Synthesis
Deng, Wei,Fan, Xiao-Nan,Ou, Hui-Dan,Yao, Zi-Jian
supporting information, (2020/04/02)
Several N,O-coordinate half-sandwich iridium complexes, 1-5, containing constrained bulky β-enaminoketonato ligands were prepared and clearly characterized. Single-crystal X-ray diffraction characterization of these complexes indicates that the iridium center adopts a distorted octahedral geometry. Complexes 1-5 showed good catalytic efficiency in the oxidative homocoupling of primary amines, dehydrogenation of secondary amines, and the oxidative cross-coupling of amines and alcohols, which furnished various types of imines in good yields and high selectivities using O2 as an oxidant under mild conditions. No distinctive substituent effects of the iridium catalysts were observed in these reactions. The diverse catalytic activity, broad substrate scope, mild reaction conditions, and high yields of the products made this catalytic system attractive in industrial processes.
