C(sp3)–H functionalization of methyl azaarenes: a calcium-catalyzed facile synthesis of (E)-2-styryl azaarenes and 2-aryl-1,3-bisazaarenes

Yaragorla, Srinivasarao; Singh, Garima; Dada, Ravikrishna

doi:10.1016/j.tetlet.2015.09.035

Cited by 50 publications

(18 citation statements)

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“…e products, trans-styryl compounds 4 [50,51], 5 and 6, were formed in rather moderate yields. However, the unreacted methyl derivatives could be easily recovered.…”

Section: Resultsmentioning

confidence: 99%

2-Oxiranyl-pyridines: Synthesis and Regioselective Epoxide Ring Openings with Chiral Amines as a Route to Chiral Ligands

Wosińska-Hrydczuk

Skarżewski

2019

Heteroatom Chemistry

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New epoxides, derivatives of pyridine, 2,2′-bipyridine, and 1,10-phenanthroline, were synthesized from the respective α-methylazaarenes. The obtained racemic 2-oxiranyl-azaarenes along with styrene oxide and trans-stilbene oxide were submitted to the ring opening with chiral primary amines as a chiral auxiliary. The most effective reaction was run in the presence of Sc(OTf)3/diisopropylethylamine for 7 days at 80°C, affording a good yield of the amino alcohols. Except for styrene oxide which gave both α- and β-amino alcohols, the reactions led regioselectively to the corresponding diastereomeric β-amino alcohols. The resulting diastereomers were separated, and the configurations of their stereogenic centers were established. The obtained enantiomerically pure 2-pyridinyl- and 6-(2,2′-bipyridinyl)-β-amino alcohols were tentatively tested as chiral ligands in the zinc-catalyzed aldol reaction.

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“…e products, trans-styryl compounds 4 [50,51], 5 and 6, were formed in rather moderate yields. However, the unreacted methyl derivatives could be easily recovered.…”

Section: Resultsmentioning

confidence: 99%

2-Oxiranyl-pyridines: Synthesis and Regioselective Epoxide Ring Openings with Chiral Amines as a Route to Chiral Ligands

Wosińska-Hrydczuk

Skarżewski

2019

Heteroatom Chemistry

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“…In 2015, our group reported a calcium‐catalyzed facile synthesis of bis azaarenes using 2‐methyl quinolines and aromatic aldehydes by refluxing in acetonitrile at 100 °C for 10–12 h (Scheme ) . When compared to the above approach (Scheme ), this method required a low temperature and short reaction times, a total of 9 examples were made with yields ranging from 78 to 86 %.…”

Section: Alkylationmentioning

confidence: 99%

“…In 2015, our group reported a calcium catalyzed reaction of 2‐methyl azaarene with isatin by refluxing in acetonitrile at 100 °C for 24–48 h (Scheme ) . When 2‐methyl quinoline was used as nucleophile against isatin, we thought of only the tert ‐alcohol formation, surprisingly one more addition of azaarene to this tert ‐alcohol resulted in the creation of 40 with all‐carbon‐quaternary center.…”

Section: Alkylationmentioning

confidence: 99%

“…Later in 2015, our group reported a calcium‐catalyzed nucleophilic addition reaction of 2‐methyl azaarene with various substituted aromatic aldehydes to produce styrylquinolines under solvent‐free, conditions at 130 °C for 4–5 h (Scheme ). The substrate scope was excellent and compared to the previous approaches, the yields and the reaction times are better than Scheme .…”

Section: Alkenylationmentioning

confidence: 99%

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C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

Latha

Yaragorla

2020

Eur J Org Chem

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Quinolines and their derivatives have always been promising leads for drug discovery, material applications and designing new catalysts. In the past decade, C(sp 3 )-H functionalization of 2-methyl azaarenes, particularly 2-methyl quinol- [a] ACYLATIONAlmost the early report of C(sp 3 )-H functionalization of 2methyl quinoline was performed by treating with esters using sodamide or potassium amide as the base. This reaction followed the nucleophilic substitution at the sp 2 center of the ester by the benzylic carbanion which was formed by the base treatment (Scheme 2). A total of 15 compounds were made using this method with the yields ranging from 14-62 %. [11] After a couple of years, another report [12] appeared for this transformation, where 2-methyl quinoline and esters were reacted in the presence of phenyllithium to give corresponding acylated quinolines in 36-80 % yields. Later in 1974, J. F. Wolfe reported another approach by treating 2-methyl quinoline with esters refluxed in dimethoxyethane (DME) using sodium hydride for 1-48 h to obtain the corresponding acylated quinolines in 44-98 % yields. [13] Scheme 2. Minireview

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“…Later, Wang and the co‐workers presented a catalyst‐free synthesis of the related compounds via a similar coupling procedure (Scheme b) . More recently, the condensation of 2‐alkylazaarenes with aldehydes has also been nicely demonstrated to synthesize ( E )‐2‐alkenylazaarenes in the presence of Lewis acids, or under catalyst‐free conditions, (Scheme c). However, to the best of our knowledge, the dehydrogenative coupling of (hetero)aryl‐fused 2‐alkylcyclic amines 1 with aldehydes 2 to give the ( E )‐2‐alkenylazaarenes 3 remains an unresolved goal (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of (E)‐2‐Alkenylazaarenes via Dehydrogenative Coupling of (Hetero)aryl‐fused 2‐Alkylcyclic Amines and Aldehydes with a Cobalt Nanocatalyst

et al. 2018

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To date, the synthesis of (E)‐2‐alkenylazaarenes via the condensation of 2‐methyl N‐heteroarenes with aldehydes or their equivalents has been well demonstrated. However, the direct formation of such a class of useful compounds from extensively distributed 2‐alkylcyclic amine motifs remains an unresolved goal. Herein, by employing the nitrogen‐silica‐doped carbon (Vulcan XC‐72R) as the support, we have developed a low‐loading cobalt nanocatalyst (Co/N‐Si‐C). The combination of such a catalyst with p‐nitrobenzoic acid and molecular O2 exhibits excellent catalytic performance towards the dehydrogenative coupling of (hetero)aryl‐fused 2‐alkylcyclic amines with aldehydes to afford the (E)‐2‐alkenylazaarenes. In the reaction, effective capture of the partially dehydrogenated cyclic amine motifs appears to be the key strategy to address the issue of the chemoselectivity. The developed catalytic transformation proceeds with the merits of broad substrate scope, good functional group tolerance, high atom‐efficiency, use of an earth‐abundant and reusable cobalt catalyst and molecular O2 as a green oxidant, which offers an important basis for the direct conversion of inert cyclic amine units into the functional frameworks.

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C(sp3)–H functionalization of methyl azaarenes: a calcium-catalyzed facile synthesis of (E)-2-styryl azaarenes and 2-aryl-1,3-bisazaarenes

Cited by 50 publications

References 47 publications

2-Oxiranyl-pyridines: Synthesis and Regioselective Epoxide Ring Openings with Chiral Amines as a Route to Chiral Ligands

2-Oxiranyl-pyridines: Synthesis and Regioselective Epoxide Ring Openings with Chiral Amines as a Route to Chiral Ligands

C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

Synthesis of (E)‐2‐Alkenylazaarenes via Dehydrogenative Coupling of (Hetero)aryl‐fused 2‐Alkylcyclic Amines and Aldehydes with a Cobalt Nanocatalyst

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C(sp3)–H functionalization of methyl azaarenes: a calcium-catalyzed facile synthesis of (E)-2-styryl azaarenes and 2-aryl-1,3-bisazaarenes

Cited by 50 publications

References 47 publications

2-Oxiranyl-pyridines: Synthesis and Regioselective Epoxide Ring Openings with Chiral Amines as a Route to Chiral Ligands

2-Oxiranyl-pyridines: Synthesis and Regioselective Epoxide Ring Openings with Chiral Amines as a Route to Chiral Ligands

C(sp3)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds

Synthesis of (E)‐2‐Alkenylazaarenes via Dehydrogenative Coupling of (Hetero)aryl‐fused 2‐Alkylcyclic Amines and Aldehydes with a Cobalt Nanocatalyst

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C(sp³)‐H Functionalization of 2‐Methyl Azaarenes: Highly Facile Approach to Aza‐Heterocyclic Compounds