Copper-catalyzed cross-dehydrogenative-coulping (CDC) of coumarins with cyclic ethers and cycloalkane

Recent Developments in Transition Metal‐Catalyzed Cross‐Dehydrogenative Coupling Reactions of Ethers and Thioethers

“…Within a month of this report on coumarin and flavone C(sp 2 )−C(sp 3 ) coupling with ethers, Huang, Yusheng Wu and Yangjie Wu showed that it was possible to couple coumarins to cyclic ethers and alkanes using copper acetate as catalyst, provided KI was used as an additive, although in the case of simple alkanes the additive was not required . C‐3 functionalized coumarins were obtained in moderate to excellent yields (Scheme ) . The coumarin motif is present in many naturally occurring and synthetic substances of medicinal interest, and this structural unit is also often used in drug discovery.…”

Cross-dehydrogenative coupling of coumarins with Csp3–H bonds using an iron–organic framework as a productive heterogeneous catalyst

“…11 Wang et al synthesized a variety of C-3 functionalized coumarins via the Cu(OAc) 2 catalyzed reaction with cyclic ethers and cycloalkanes. 12 Cao et al developed a novel approach for the direct Csp 2 -H radical triuoromethylation of coumarins in the presence of Mn(OAc) 3 . 13 Zhou et al reported the cross-dehydrogenative coupling of coumarins with benzylic Csp 3 -H bonds utilizing Cu(OAc) 2 catalyst.…”

Visible Light‐Induced Regioselective Decarboxylative Alkylation of the C(sp2)−H Bonds of Non‐Aromatic Heterocycles

“…Non-aromatic heterocycles, such as coumarins, quinolinones, and quinoxalinones, are a class of significant organic compounds that are found in natural products, pharmaceuticals, and material chemistry. [1] Over the past decade, extensive research efforts have been devoted to methodological studies of the construction [2] and CÀ H functionalization [3][4][5][6][7][8][9][10][11][12][13][14] (e. g., arylation, [3] olefination, [4] phosphorylation, [5] and amination [6] ) of these scaffolds to enhance their properties for further application. Although alkylated non-aromatic heterocycles are valuable in various fields, [1] their direct and general syntheses via C(sp 2 )À H bond alkylation are limited.…”

“…[9] Recently, the oxidative alkylation of these heterocycles as an alternative method has been intensely studied via reactive radical intermediates (Scheme 1, eq 2). [10][11][12][13][14] Despite these important advances, current methods suffer from elevated reaction temperatures and the use of strong oxidants. Due to the common use of peroxides as radical initiators and terminal oxidants, the substrate scope is limited to those with a relatively weak CÀ H bond that can be selectively and homolytically cleaved, such as alkylbenzenes, [10] tertiary amines [11] and (cyclo)alkyl ethers [12] as well as cycloalkanes, [10c,12a,d,e,13] restricting the application of this strategy.…”

“…Initially, the organic and inorganic bases, such as DABCO (triethylenediamine), DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), Et 3 N, TMEDA (N,N,N',N'-tetramethylethylenediamine), and Cs 2 CO 3 , were examined as additives ( Table 1, entries [2][3][4][5][6], and the addition of DABCO provided an excellent yield for 3 aa (85%, Table 1, entry 2). However, the reaction was suppressed by the addition of an acid (i. e., CF 3 COOH and CH 3 COOH), and only a trace amount of 3 aa was observed ( [9][10][11][12]. In the absence of the photocatalyst or light, no desired product was observed ( Table 1, entries 15 and 16).…”