Covalent Organic Framework as a Heterogeneous Ligand for the Regioselective Oxidative Heck Reaction

Abstract

A simple imine-based covalent organic framework (COF) as heterogeneous ligand for PdII-promoted Heck reaction is reported. Good regioselectivity for a wide range of electronically unbiased olefins is obtained (linear/branched >100:1 in most cases). Related tests and density functional theory calculations are used to explore the reason underlying the high selectivity. This research opens a route for COF as an intriguing platform to control regioselectivity catalysis.

δ-Lactones—A New Class of Compounds That Are Toxic to E. coli K12 and R2–R4 Strains

“…The biological activity of six-membered lactones (δ-lactones) is far less investigated with respect to lactams. It is probably due to the fact that synthesis of lactams is much more expanded [ 36 , 37 , 38 , 39 , 40 ]. Several methods used for lactams synthesis, such as one-pot, BF 3 ·OEt 2 -mediated reaction of various substituted arenes with azido alkanoic acid chlorides [ 41 ], irydium catalyzed aminolysis of lactones and amines via aminolysis of lactone, N-alkylation of amine with hydroxyamide, intramolecular transamidation of aminoamide transformation [ 42 ], or a metal-free selective oxidation of cyclic secondary and tertiary amines using molecular iodine [ 42 ], cannot be used for lactones synthesis.…”

“…The synthesis of unsaturated secondary alcohols 3 ( Figure 2 ) was carried out following the procedure described by others and Gaylord and Becker [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ]. A solution of aryl bromide 1 (0.08 mol) in diethyl ether ( Figure 2 ) was added dropwise to magnesium turnings (0.08 mol) and heated under reflux for 4 h. The mixture was cooled on ice and a solution of 3-methyl crotonaldehyde 2 in diethyl ether ( Figure 2 ) was added dropwise and stirred for 24 h. The mixture was dissolved in diethyl ether and added to ice and water.…”

“…The analysis of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was performed on the basis of the original method described in detail others and by Prost [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ] with its individual modifications for specific compounds analyzed and described in the works [ 5 , 6 , 7 , 8 , 9 ].…”

Nanoscale covalent organic frameworks as theranostic platforms for oncotherapy: synthesis, functionalization, and applications

“…However, the interlayer distance of $3-4Å of COFs makes the N atoms in the linkages come close to each other, which facilitates the insertion of metal ions between the layers and promotes the formation of coordination bonds. 64,356 In addition, it is benecial for imine-linked COFs to x metal ions by introducing hydroxyl groups, [365][366][367] carboxyl groups, 368 and pyridine 369 to the monomers, since additional coordination atoms are provided. For example, NiCl 2 and hydroxyl-containing RIO-12 COF were reuxed in ethanol under basic conditions, and Ni 2+ was coordinated to the N-salicylideneaniline unit in RIO-12 to form a catalyst for the Suzuki-Miyaura cross-coupling reaction.…”

Covalent Organic Frameworks in Catalytic Organic Synthesis

“…Similarly, Ji et al also established a COF (COF-BTDH, Figure 9, Table 8) recently to embed Pd NPs and catalyze Heck reaction with high regioselectivity (Scheme 51, c). [101] This work explored a wide substrate scope and all reaped medium to great yields in low temperature, but extra metallic additive Cu(OTf) 2 was needed.…”