Decarboxylation‐Initiated Intermolecular Carbon‐Heteroatom Bond Formation

Abstract

Carboxylic acids are among the most used feedstock chemicals due to their great structural diversity and easy handling. The use of carboxylic acids and their derivatives in decarboxylative couplings has proven to be a valuable tool for the construction of C−C and C‐heteroatom bonds. This synthetic strategy provides a complementary bond disconnection to traditional cross‐coupling methods. In this review, we provide a comprehensive overview of decarboxylation‐initiated intermolecular C‐heteroatom bond formation, outlining several main mechanistic concepts combined with early examples and highlighting the achievements made in the past decade until January 2021. In these reactions, carboxylic acids and their derivatives undergo initial decarboxylation and then react with other heteroatom electrophiles and nucleophiles, thus replacing the carboxylate group with a valuable and prevalent heteroatom functionality.

Decarboxylation of Paraconic Acids by a Silver(I) Nitrate/Persulfate Combination: An Entry to β-Nitro- and β-Hydroxy γ-Butyrolactones

“…Paraconic acids 1 were synthesized according to the literature procedures. [1] Physical and spectroscopic data of paraconic acids 1a, 1b, 1d-1h, 1j, 1l, and 1m are consistent with those previously reported. Physical and spectroscopic data of previously unreported 1c, 1i, and 1k are reported herein.…”

“…3i: Rf 0.10 (1:6:4, EtOAc:acetone:hexanes). 1 H NMR (500 MHz, CDCl3, integrated equally for trans-and cis-3i, trans-3i marked*): δ 4.20 (app. dd of ABX, JBX = 4.4 Hz, JAX = 6.9 Hz, 1H, CH*), 4.17 (app.…”

“…Rf 0.65 (1:100, EtOAc:CH2Cl2). 1 H NMR (400 MHz, CDCl3): δ 7.43−7.29 (m, 5H, ArH), 5.30 (app. dd of ABX, JBX = 0.8 Hz, JAX = 6.8 Hz, 1H, CH), 3.05 (ABq of ABX, JBX = 0.8 Hz, JAB = 18.2 Hz, 1H, CHH), 2.70 (ABq of ABX, JAX = 6.8 Hz, JAB = 18.2 Hz, 1H, CHH), 1.67 (s, 3H, CH3) ppm.…”

Biaryl Synthesis via Electrooxidative Transition-Metal-Catalyzed C–H Activation

“…Both previously mentioned protocols 28,29 require strong N-based directing groups which are not easy to install and remove after C-H functionalization. In this regard, carboxylate groups represent the most desirable directing groups for C-H activation, since aromatic carboxylic acids are widely accessible in great structural variety and can be removed tracelessly by protodecarboxylation [30][31][32][33] or serve as a leaving group in decarboxylative cross-couplings after acted as directing group. [33][34][35] However, in comparison to pyridyl groups, they coordinate only weakly, making their use as directing group in catalytic reactions based on directed C-H metalations more difficult.…”

Palladium‐Catalyzed Decarboxylative 1,2‐Addition of Carboxylic Acids to Glyoxylic Acid Esters

“…In the last years decarboxylative cross-couplings between benzoic acids and aryl halides [17][18][19][20][21] as well as decarboxylative couplings as carbon-heteroatom bond forming reactions have received considerable attention. [22] On the other hand, replacement of organometallic nucleophiles with carboxylic acids in classical 1,2-addition reactions to electrophilic aldehydes or imines have been only sparsely studied. The group of Wu disclosed a palladium-catalyzed decarboxylative 1,2-addition of benzoic acids to electron-deficient arylaldehydes and their corresponding N-tosyl imines.…”