K2CO3/18-Crown-6-Catalyzed Selective H/D Exchange of Heteroarenes with Bromide as a Removable Directing Group.

The K2CO3/18-crown-6-catalyzed H/D exchange of heretoarenes in high atom % deuterium incorporation is disclosed. The use of a weak base as a catalyst leads to excellent site selectivity and broad functional group tolerance. Control experiments indicated that the use of bromide, which enhances the adjacent C-H bond reactivity, as a removable directing group is essential. Moreover, conversion of bromide to other functional groups is also performed to construct other useful deuterated compounds.

Silver salt enabled H/D exchange at the ß-position of thiophene rings: synthesis of fully deuterated thiophene derivatives.

We disclose a silver catalyzed H/D exchange reaction, which can introduce the deuterium atom at the ß position of thiophene rings without the assistance of any coordinating groups. The advantages of this reaction include operation in open air, usage of D2O as the deuterium source, good tolerance to a range of functional groups and obtaining high atom% deuterium incorporation. In addition, this H/D exchange reaction is employed for direct deuteration of a thiophene based monomer, which is usually prepared by multistep synthesis from expensive deuterated starting materials.

C-H Bond Functionalization of (Hetero)aryl Bromide Enabled Synthesis of Brominated Biaryl Compounds.

Aryl bromide is one of the most important compounds in organic chemistry, because it is widely used as synthetic building blocks enabling quick access to a wide array of bioactive molecules, organic materials, and polymers via the versatile cutting-edge transformations of C-Br bond. Direct C-H bond functionalization of aryl bromide is considered to be an efficient way to prepare functionalized aryl bromides; however, it is rarely explored possibly due to the relatively low reactivity of aryl bromide toward C-H bond activation. We herein report a palladium-catalyzed coupling reaction between aryl iodide and aryl bromide for preparing brominated biaryl compounds via a silver-mediated C-H bond activation pathway.

Synthesis of Multideuterated (Hetero)aryl Bromides by Ag(I)-Catalyzed H/D Exchange.

Deterium-labeled (hetero)aryl bromide is one of the most widespread applicable motifs to achieve important deuterated architectures for various scientific applications. Traditionally, these deterium-labeled (hetero)aryl bromides are commonly prepared via multistep syntheses. Herein, we disclose a direct H/D exchange protocol for deuteration of (hetero)aryl bromides using Ag2CO3 as catalyst and D2O as deuterium source. This protocol is highly efficient, simply manipulated, and appliable for deuterium-labeling of over 55 (hetero)aryl bromides including bioactive druglike molecules and key intermediates of functional materials. In addition, this method showed distinguishing site-selectivity toward the existing transition-metal-catalyzed HIE process, leading to multideuterated (hetero)aryl bromides in one step.

Ag(i)-Mediated hydrogen isotope exchange of mono-fluorinated (hetero)arenes.

An efficient approach to install deuterium into mono-fluorinated (hetero)arenes by a Ag2CO3/Sphos-mediated HIE protocol with D2O as the deuterium source has been disclosed. This method showed a specific site selectivity of deuteration at the α-position of the fluorine atom, which is complementary to the existing transition metal-catalyzed HIE process.

Correction: Cascade alkylation and deuteration with aryl iodides via Pd/norbornene catalysis: an efficient method for the synthesis of congested deuterium-labeled arenes.

Correction for 'Cascade alkylation and deuteration with aryl iodides via Pd/norbornene catalysis: an efficient method for the synthesis of congested deuterium-labeled arenes' by Lei Guo et al., Chem. Commun., 2019, 55, 8567-8570.

Ag2CO3-Catalyzed H/D Exchange of Five-Membered Heteroarenes at Ambient Temperature.

Ag2CO3-catalyzed hydrogen isotope exchange of five-membered heteroarenes is disclosed. The reaction can be conducted in the open air, at ambient temperature, and with D2O as deuterium source. Moreover, this protocol showed orthogonal site selectivity to existing technology, thereby greatly expanding the scope of substrates for HIE reaction. The mechanistic study indicated that the carbonate group plays a crucial role to achieve high levels of deuterium incorporation by lowering the activation energy of H/D exchange process.

Cascade alkylation and deuteration with aryl iodides via Pd/norbornene catalysis: an efficient method for the synthesis of congested deuterium-labeled arenes.

An efficient approach for synthesizing congested deuterium-labeled arenes via cascade alkylation and deuteration with aryl iodides has been disclosed. We found that the adoption of sodium formate-d as a deuterium source is the key for achieving high deuterium incorporation >98%.