Arylation Of Imidazo Research Articles

Construction of a Bifunctional Pd(0)‐CALB@SiO2 Hybrid Catalyst for the Synthesis and Arylation of Imidazo[1,2‐a]pyridine in One Pot

AbstractHerein, we describe an efficient strategy for the construction of enzyme‐metal biohybrid catalyst [Pd(0)‐CALB@SiO2] via encapsulation of Candida antarctica lipase B and Pd(0) within silica. Next, the applicability of the newly constructed biohybrid was demonstrated by catalyzing the sequence of Groebke‐Blackburn‐Bienayme (GBB) multicomponent reaction and Suzuki‐Miyaura coupling in a single‐pot to produce clinically significant imidazo[1,2‐a]pyridine derivatives. Interestingly, both entities, i.e., CALB enzyme and Pd(0)‐metal of hybrid catalyst, exhibited good catalytic activity during this approach. Further, the generality of this protocol was explored by using differently substituted boronic acid, which gave related products in 49–87 % isolated yield. Next, the synthetic utility was proved by set‐up a gram scale reaction which provided the complementary product in 81 % yield. Also, the developed biohybrid was found to be reusable up to five catalytic cycles.

Regioselective Base‐controlled Pd‐catalyzed Arylation of Imidazo[1,2‐a]pyridines: leading selectivity at C8 position by N‐chelation over O‐chelation

AbstractA base controlled operationally simple catalytic system for the regioselective arylation of 2‐aryl‐imidazo[1,2‐a]pyridine by Pd catalyzed C−H activation has been developed. Herein, we report Pd/Ag2CO3 promoted C8 arylation of the heterocycles by overriding the N‐chelation on O‐chelation. In this way, various examples have been synthesized in good to excellent yield. Furthermore, Pd/t‐BuOK system has been developed for the novel deformylative C3 arylation of 2‐aryl‐imidazo[1,2‐a]pyridine. The choice of the catalytic system is also demonstrated for heteroarylation. Both standardized protocols have been explored with broad substrate scope and good functional group tolerance.

ChemInform Abstract: Regioselective Direct C‐3 Arylation of Imidazo[1,2‐a]pyridines with Aryl Tosylates and Mesylates Promoted by Palladium—Phosphine Complexes.

Direct C-3 arylation of imidazo[1,2-a]pyridines with aryl tosylates and mesylates has been accomplished by employing palladium(II) acetate associated with SPhos (2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl) or L1 (2-(2-(diisopropylphosphino)phenyl)-1-methyl-1H-indole). This catalyst system can be applied to a wide range of aryl sulfonates and shows excellent C-3 regioselectivity of imidazo[1,2-a]pyridine. These results represent the first examples of using tosylate- and mesylate-functionalized arenes as the electrophile partners for this regioselective direct arylation.

ChemInform Abstract: Sequential C3 and C5 Direct C—H Arylation of Imidazo[1,2‐a]pyrazines with (Hetero)aryl Bromides.

ChemInformVolume 46, Issue 4 Heterocyclic Compounds ChemInform Abstract: Sequential C3 and C5 Direct C—H Arylation of Imidazo[1,2-a]pyrazines with (Hetero)aryl Bromides. Brett M. Johnson, Brett M. Johnson Discovery Chem. Group, Genentech Inc., South San Francisco, CA 94080, USASearch for more papers by this authorMalcolm P. Huestis, Malcolm P. Huestis Discovery Chem. Group, Genentech Inc., South San Francisco, CA 94080, USASearch for more papers by this author Brett M. Johnson, Brett M. Johnson Discovery Chem. Group, Genentech Inc., South San Francisco, CA 94080, USASearch for more papers by this authorMalcolm P. Huestis, Malcolm P. Huestis Discovery Chem. Group, Genentech Inc., South San Francisco, CA 94080, USASearch for more papers by this author First published: 08 January 2015 https://doi.org/10.1002/chin.201504185Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume46, Issue4January, 2015 RelatedInformation

Sequential C3 and C5 Direct C–H Arylation of Imidazo[1,2‐a]pyrazines with (Hetero)aryl Bromides

AbstractAn efficient reaction manifold for the preparation of C3/C5‐diarylimidazo[1,2‐a]pyrazines through sequential C3 and C5 direct arylation is disclosed. The two distinct palladium catalyst systems showcased herein are compatible with a wide variety of aryl and heteroaryl bromides and are also operative in a one‐pot, twofold C–H functionalization event.

ChemInform Abstract: Rhodium‐Catalyzed Highly Regioselective C—H Arylation of Imidazo[1,2‐a]pyridines with Aryl Halides and Triflates.

E-mail: cuigdut@yahoo.com.cnReceived April 8, 2013, Accepted May 13, 2013A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflateshas been reported. This process afforded a range of biaryl compounds in excellent yields and showed highactivity and broad scope. Key Words : Rhodium catalyst, Aryl halides, Regioselective arylation, Imidazo[1,2- a]pyridines, TriflatesIntroductionHeteroaromatics bearing aryl-heteroaryl bond are alwaysas one of the most important structural units frequentlyfound in biological compounds, natural products, materialschemistry, ligands.

Rhodium-Catalyzed Highly Regioselective C-H Arylation of Imidazo[1,2-a]pyridines with Aryl Halides and Triflates

E-mail: cuigdut@yahoo.com.cnReceived April 8, 2013, Accepted May 13, 2013A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflateshas been reported. This process afforded a range of biaryl compounds in excellent yields and showed highactivity and broad scope. Key Words : Rhodium catalyst, Aryl halides, Regioselective arylation, Imidazo[1,2- a]pyridines, TriflatesIntroductionHeteroaromatics bearing aryl-heteroaryl bond are alwaysas one of the most important structural units frequentlyfound in biological compounds, natural products, materialschemistry, ligands.