Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (±)-Solenopsin A

Yamaguchi, Ryohei; Nakazono, Yutaka; Matsuki, Toshitsugu; Hata, E.; Kawanisi, Mituyosi

doi:10.1246/bcsj.60.215

Cited by 68 publications

(22 citation statements)

References 37 publications

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“…Since α‐ketols 12 were obtained in 4–9 % yields in the Reissert‐type acylation of quinolines by Cu I /CH 2 Cl 2 catalytic systems, the acyl Cu species might be involved in these preferred 1,4‐addition reactions. Such a preferential formation of 1,4 adducts has been reported in Reissert‐type transformations of quinolines and pyridines by using organocopper compounds8a–8c or organometallic compounds with Cu I additives 5e,6d,8d,8e. Although details about the solvent effect22 and the role of the cationic Rh I catalyst23 for the regioselectivity remain uncertain at present, the cationic Rh I catalyst might take part in promoting the generation of N ‐acylquinolinium intermediates 13 24…”

Section: Resultsmentioning

confidence: 88%

Reissert‐Type Acylation with Acylzirconocene Chloride Complexes

et al. 2013

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In the presence of ClCO2Et, the use of CuI in MeNO2 efficiently catalyzed the Reissert‐type acylation of isoquinoline derivatives with acylzirconocene chlorides. In the reaction of quinolines with acylzirconocene chlorides, the choice of catalyst and solvent was crucial to the regioselective formation of adducts. The cationic RhI‐catalyzed reaction in MeNO2 preferentially afforded 1,2 adducts. On the other hand, the CuI‐catalyzed reaction in CH2Cl2 preferentially afforded 1,4 adducts.

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Section: Resultsmentioning

confidence: 88%

Reissert‐Type Acylation with Acylzirconocene Chloride Complexes

et al. 2013

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“…56 Com-R The D 2 -piperideine derivatives 35 lose the methoxycarbonyl group when heated with iodotrimethylsilane and are thus converted into D 1 -piperideines 1 in almost quantitative yields. 57,58 Hydrazinolysis of the C ± N bond in the Schiff's bases 36 affords the D 1 -piperideines 1 in almost quantitative yields. 59 Methyl 1-tosyl-1,4,5,6-tetrahydronicotinate has been found to undergo an unexpected transformation on heating with thiourea yielding acid 37.…”

Section: Anolytementioning

confidence: 99%

“…59 2-Methyl-6-octyl-3,4,5,6-tetrahydropyridine is reduced by lithium aluminium hydride in THF at 778 to 0 8C giving rise to a mixture of cis-and trans-isomers of the corresponding piperidine in 5 : 7 ratio; their overall yield is 70%. 57,58 On treatment with lithium aluminium hydride and trimethylaluminium in hexane, 2-methyl-6-undecyl-3,4,5,6-tetrahydropyridine is reduced to give 2-methyl-6-undecylpiperidine [alkaloid (+)-solenopsine] as a mixture of diastereoisomers trans-122a and cis-122a in 95 : 5 ratio. 57,58,119…”

Section: Reductionmentioning

confidence: 99%

See 1 more Smart Citation

2,3,4,5-Tetrahydropyridine (Δ¹-piperideine) and its derivatives. Synthesis and chemical properties

Shvekhgeimer¹

1998

Russ. Chem. Rev.

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We study the influence of the tetragonalization occurring during the martensitic phase transition on the exchange interactions in Ni 2 MnGa Heusler alloy using first-principles calculations in conjunction with the frozen-magnon approximation. We show that the tetragonalization alters only the exchange constants characterizing the Mn-Mn interactions. Calculated Curie temperatures within the random-phase approximation are found to agree with experimental data. Moreover, we study the temperature dependence of the magnetization and the small deviation from the experimental data exactly at the temperature of the phase transition is discussed. Obtained results agree with previous theoretical results using Liechtenstein's formula to calculate the exchange constants and the Monte Carlo simulation technique to estimate the Curie temperature.have studied the exchange constants for the stoichiometric Ni 2 MnGa alloys for three values of the c/a ratio (c/a = 0.95, 1 and 1.25) using Liechtenstein's formula [31,32] while Monte Carlo simulations have been employed to estimate a Curie temperature of 375 K for the cubic austenitic phase [33]. Recently, the same group of authors have studied the exchange constants for the off-stoichiometric alloys both in the austenitic and martensitic phases [34,35], while Ghosh and Sanyal have focused only in the austenitic phase [36].

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“…Alkyl Grignard reagents like butyl magnesium bromide gave a mixture of 1, 2 and 1,4-dihydropyridines (1.5 and 1.6) , whereas harder nucleophiles like MeMgBr and alkynyl Grignard reagents afforded higher selectivity for the 1, 2-dihydropyridine (1.7) as shown in scheme 1.6. 11,12 When the organometallic reagent was varied to the softer butylzinc chloride, increased 1, 4-dihydropyridine product (1.6) was observed. Scheme 1.6 1, 2-and 1, 4-dihydropyridine synthesis.…”

Section: Substitution Reactions Of Pyridinementioning

confidence: 99%

Metal mediated intramolecular transformations of pyridine substrates

Pawar¹

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v group, Sharu and Pradeep and the present members Ashaba, Chris, Dan for all the help and support. Sharu, Pradeep and myself have always been there for one another and taught ourselves and each other many tools in chemistry and had a lot of fun time. I would like to thank Ashish for being there with me whenever I needed him and making life easy. I would like to thank all my friends Nisarga, Abhinaba and Suman for their support and encouragement. I would like to specially thank Sampada for helping me for formatting this thesis. This would have not been possible without the support and blessings of my parents Shri. Shiwaji and Smt. Sumadevi, I cannot thank my wife and kids enough for being supportive and making my life wonderful and keep me working towards my goal. In the end I would like to thank all the people I have missed and who have directly or indirectly helped me in achieving my dream. vi ABSTRACT Nature continuously provides fascinating and complicated structures which offer synthetic chemists amazing opportunities for the design of new methods for the natural product synthesis. Nitrogen containing aza-heterocycles are of unparalleled importance in natural product, bioorganic and medicinal chemistry. Pyridine in particular is one of the most common aza-heterocycles encountered in natural products, medicinal and materials chemistry. Pyridine derivatives also serve as precursors to functionalized piperidines, which are likewise common structural motifs in bioactive and functionalized materials.Thus, developing synthetic methods suitable for the manipulation of pyridine ring systems remains an important objective in the organic chemistry community.We approached this objective by two different routes. In the first method, we used the nucleophilicity of the benzylic position of the 4-alkyl pyridine substrates to engage in gold (I) catalyzed 5 or 6-endo dig cyclizations with attached alkynyl amide groups.Processing of the resulting cycloadducts under hydrolytic conditions then afforded substituted pyridines with functionalized lactams.In the second approach, we investigated the feasibility of Pd-catalyzed cyclization of 3-substituted pyridines. It was envisioned that Pd(0) catalysts could react with alkyne substituents positioned along the pyridine periphery such that a nucleophilic alkynyl moiety would be generated. Activation of the pyridine by N-alkylation or acylation would then result in intramolecular cyclization. Rather than the desired reaction pathway, however, only products of alkyne hydroarylation were observed.

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Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (±)-Solenopsin A

Abstract: Reaction of the pyridines (I) with the alkenyl or alkynyl Grignard reagents (II) in the presence of methyl chloroformate (III) yields the dihydropyridines (IV) with an α‐regioselectivity of > 98% in all cases.

Cited by 68 publications

References 37 publications

Reissert‐Type Acylation with Acylzirconocene Chloride Complexes

Reissert‐Type Acylation with Acylzirconocene Chloride Complexes

2,3,4,5-Tetrahydropyridine (Δ¹-piperideine) and its derivatives. Synthesis and chemical properties

Metal mediated intramolecular transformations of pyridine substrates

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Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (±)-Solenopsin A

Abstract: Reaction of the pyridines (I) with the alkenyl or alkynyl Grignard reagents (II) in the presence of methyl chloroformate (III) yields the dihydropyridines (IV) with an α‐regioselectivity of > 98% in all cases.

Cited by 68 publications

References 37 publications

Reissert‐Type Acylation with Acylzirconocene Chloride Complexes

Reissert‐Type Acylation with Acylzirconocene Chloride Complexes

2,3,4,5-Tetrahydropyridine (Δ1-piperideine) and its derivatives. Synthesis and chemical properties

Metal mediated intramolecular transformations of pyridine substrates

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2,3,4,5-Tetrahydropyridine (Δ¹-piperideine) and its derivatives. Synthesis and chemical properties