Synthesis of (Hetero)Aryl Functionalized Azaindoline Derivatives By Palladium-Catalyzed Domino Heck Cyclization/Hiyama Cross-Coupling

Synthesis ◽  
2021 ◽  
Author(s):  
Hao Ye ◽  
Ruotong Zhang ◽  
Xiaolong Xia ◽  
Yue Ding ◽  
Meihui Sun ◽  
...  

A palladium-catalyzed domino Heck cyclization/Hiyama cross-coupling has been achieved for the synthesis of (hetero)aryl functionalized azaindoline derivatives bearing all-carbon quaternary centers with yields of 46-85%. The synthetic versatility of this protocol has been highlighted by the gram-scale synthesis and modification of aryl-containing complex bioactive molecules.

Synlett ◽  
2019 ◽  
Vol 30 (09) ◽  
pp. 1008-1014 ◽  
Author(s):  
Kuai Wang ◽  
Wangqing Kong

A Ni-catalyzed enantioselective reductive diarylation of alkenes through a tandem Heck cyclization/cross coupling of two structurally distinguished aryl bromides is accomplished for the first time. This reaction takes place under very mild conditions with high efficiency and tolerates a variety of functional groups. Thus, it provides a rapid access to various medicinally relevant bis-heterocycles containing all-carbon quaternary centers with very high enantioselectivity.


Synthesis ◽  
2021 ◽  
Author(s):  
chang wen ◽  
Qing Han Li ◽  
Chuan Wu ◽  
ruiqiang Luo ◽  
Feng Chen

A highly efficient and simple route for the synthesis of 2-substituted benzo[b]furans has been developed by Palladium catalyzed the cross-coupling reaction of 2-halobenzo[b]furans with aryl, alkynyl and alkylaluminum reagents. Various 2-aryl, 2-alkynyl and 2-alkyl substituted benzo[b]furans derivatives can be obtained with 23-97% isolated yields using 2-3 mol% PdCl2/ 4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[b]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl trimethylsilanyl and benzyl groups worked efficiently with 2-halobenzo[b]furans as well, and three bioactive molecules with 2-substituted benzo[b]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[b]furans derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.


2020 ◽  
Author(s):  
Arup Mondal ◽  
Manuel van Gemmeren

Alkynes are highly attractive motifs in organic synthesis due to their presence in natural products and bioactive molecules as well as their versatility in a plethora of subsequent transformations. A common procedure to insert alkynes into hetero(arenes), such as the thiophenes studied herein, consists of a halogenation followed by a Sonogashira cross-coupling. The regioselectivity of this approach depends entirely on the halogenation step. Similarly, direct alkynylations of thiophenes have been described that follow the same regioselectivity patterns. Herein we report the development of a palladium catalyzed C–H activation/alkynylation of thiophenes. The method is applicable to a broad range of thiophene substrates. For 3-substituted substrates where controlling the regioselectivity between the C2 and C5 position is particularly challenging, two sets of reaction conditions enable a regiodivergent reaction, giving access to each regioisomer selectively. Both protocols use the thiophene as limiting reagent and show a broad scope, rendering our method suitable for late-stage modification.


2020 ◽  
Author(s):  
Arup Mondal ◽  
Manuel van Gemmeren

Alkynes are highly attractive motifs in organic synthesis due to their presence in natural products and bioactive molecules as well as their versatility in a plethora of subsequent transformations. A common procedure to insert alkynes into hetero(arenes), such as the thiophenes studied herein, consists of a halogenation followed by a Sonogashira cross-coupling. The regioselectivity of this approach depends entirely on the halogenation step. Similarly, direct alkynylations of thiophenes have been described that follow the same regioselectivity patterns. Herein we report the development of a palladium catalyzed C–H activation/alkynylation of thiophenes. The method is applicable to a broad range of thiophene substrates. For 3-substituted substrates where controlling the regioselectivity between the C2 and C5 position is particularly challenging, two sets of reaction conditions enable a regiodivergent reaction, giving access to each regioisomer selectively. Both protocols use the thiophene as limiting reagent and show a broad scope, rendering our method suitable for late-stage modification.


2020 ◽  
Author(s):  
Jian Cao ◽  
Ernest Armenta ◽  
Lisa Boatner ◽  
Heta Desai ◽  
Neil Chan ◽  
...  

Bioorthogonal chemistry is a mainstay of chemoproteomic sample preparation workflows. While numerous transformations are now available, chemoproteomic studies still rely overwhelmingly on copper-catalyzed azide –alkyne cycloaddition (CuAAC) or 'click' chemistry. Here we demonstrate that gel-based activity-based protein profiling (ABPP) and mass-spectrometry-based chemoproteomic profiling can be conducted using Suzuki–Miyaura cross-coupling. We identify reaction conditions that proceed in complex cell lysates and find that Suzuki –Miyaura cross-coupling and CuAAC yield comparable chemoproteomic coverage. Importantly, Suzuki–Miyaura is also compatible with chemoproteomic target deconvolution, as demonstrated using structurally matched probes tailored to react with the cysteine protease caspase-8. Uniquely enabled by the observed orthogonality of palladium-catalyzed cross-coupling and CuAAC, we combine both reactions to achieve dual protein labeling.


2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.


2020 ◽  
Author(s):  
Evgeny Tretyakov ◽  
Svetlana Zhivetyeva ◽  
Pavel Petunin ◽  
Dmitry Gorbunov ◽  
Nina Gritsan ◽  
...  

<p>Verdazyl-nitroxide diradicals were synthesized using the palladium-catalyzed cross-coupling reaction of the corresponding iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields (up to 82%). The synthesized diradicals were found to be highly thermally stable and have a singlet (D<i>E</i><sub>ST</sub> » -64 cm<sup>–1</sup>) or triplet ground state (D<i>E</i><sub>ST</sub> ³ 25 and 100 cm<sup>–1</sup>), depending on which canonical hydrocarbon diradical type they belong to. Upon crystallization, triplet diradicals form unique one-dimensional (1D) spin <i>S</i> = 1 chains of organic diradicals with intrachain ferromagnetic coupling of <i>J</i>′/<i>k</i><sub>B</sub> from 3 to 6 K.</p>


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