- Novel reduction of 3-hydroxypyridine and its use in the enantioselective synthesis of (+)-pseudoconhydrine and (+)-N-methylpseudoconhydrine
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3-Hydroxypyridine is reduced with sodium borohydride in the presence of benzyl chloroformate to give 1-benzyloxycarbonyl-5-hydroxy-2-piperideine which is transformed into (+)-pseudoconhydrine and (+)-N-methylpseudoconhydrine in five steps involving a lipa
- Sakagami, Hideki,Kamikubo, Takashi,Ogasawara, Kunio
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- Enantioselective Preparation and Hydroboration of Cyclic Enamides: Synthesis of (2S)-Pseudoconhydrine
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Successive treatment of 2-alkyl-1-hydroxy-6-carbonylsultampiperidines 1 with NaH and an acylating agent/pyridine in boiling toluene affords optically pure 1-acyl-2-alkyl-1,2,3,4-tetrahydropyridines 2.Hydroboration/oxidation of N-benzoylenamides 2f and 2g furnishes trans-2-alkyl-1-benzyl-5-hydroxypiperidines 5f and 5g, respecively.Hydrogenolysis of 5f provides pure (2S)-pseudoconhydrine (7), in 3 steps from 1, R2=n-C3H7 (31percent overall yield).
- Oppolzer, Wolfgang,Bochet, Christian G.
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- Catalytic Kinetic Resolution of Disubstituted Piperidines by Enantioselective Acylation: Synthetic Utility and Mechanistic Insights
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The catalytic kinetic resolution of cyclic amines with achiral N-heterocyclic carbenes and chiral hydroxamic acids has emerged as a promising method to obtain enantio-enriched amines with high selectivity factors. In this report, we describe the catalytic kinetic resolution of disubstituted piperdines with practical selectivity factors (s, up to 52) in which we uncovered an unexpected and pronounced conformational effect resulting in disparate reactivity and selectivity between the cis- and trans-substituted piperidine isomers. Detailed experimental and computational studies of the kinetic resolution of various disubstituted piperidines revealed a strong preference for the acylation of conformers in which the α-substituent occupies the axial position. This work provides further experimental and computational support for the concerted 7-member transition state model for acyl transfer reagents and expands the scope and functional group tolerance of the secondary amine kinetic resolution.
- Wanner, Benedikt,Kreituss, Imants,Gutierrez, Osvaldo,Kozlowski, Marisa C.,Bode, Jeffrey W.
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supporting information
p. 11491 - 11497
(2015/09/21)
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- A novel route to 6-substituted piperidin-3-ols via domino cyclization of 2-hydroxy-6-phosphinyl-5-hexenyl tosylates with primary amines: Synthesis of (±)-pseudoconhydrine and (±)- epi -pseudoconhydrine
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2-Hydroxy-6-phosphinyl-5-hexenyl tosylates, oxirane ring-opening products derived from glycidyl tosylates and phosphinyl-substituted allyl anions, undergo domino SN2-Michael reactions with primary amines to give 6-phosphinylmethylpiperidin-3-ols. The phosphinyl unit can be used in Horner olefination reactions. This approach is applied to the synthesis of racemic pseudoconhydrine and its epimer. Georg Thieme Verlag Stuttgart New York.
- Scherner, Cathrin,Ergüden, Jens-Kerim,Adiwidjaja, Gunadi,Schaumann, Ernst
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p. 2506 - 2514
(2014/11/26)
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- A Novel Route to 6-Substituted Piperidin-3-ols via Domino Cyclization of 2-Hydroxy-6-phosphinyl-5-hexenyl Tosylates with Primary Amines: Synthesis of (±)-Pseudoconhydrine and (±)- epi -Pseudoconhydrine
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2-Hydroxy-6-phosphinyl-5-hexenyl tosylates, oxirane ring-opening products derived from glycidyl tosylates and phosphinyl-substituted allyl anions, undergo domino SN2-Michael reactions with primary amines to give 6-phosphinylmethylpiperidin-3-ols. The phosphinyl unit can be used in Horner olefination reactions. This approach is applied to the synthesis of racemic pseudoconhydrine and its epimer.
- Scherner, Cathrin,Ergüden, Jens-Kerim,Adiwidjaja, Gunadi,Schaumann, Ernst
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p. 2506 - 2514
(2015/12/26)
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- Asymmetric syntheses of pyrrolidine and piperidine derivatives Via regio-and stereo-selective ring-opening reactions of chiral aziridine
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Asymmetric synthesis of cyclic β-amino alcohols (pyrrolidine and piperidine derivatives) has been achieved using a chiral aziridine as the starting material. The key step of this synthetic methodology is regio- and stereo-controlled ring-opening of the chiral aziridine with acetic acid or acetyl chloride.
- Higashiyama, Kimio,Matsumura, Masataka,Kurita, Emiko,Yamauchi, Takayasu
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p. 371 - 380
(2013/08/15)
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- Synthesis of functionalized 3-hydroxypiperidines
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The synthetic versatility of three chemoenzymatically prepared hydroxypiperidine building blocks has been explored, resulting in a library of enantiopure functionalized piperidines. Key steps involved N-acyliminium ion-mediated CC-bond formation and cross-metathesis reactions, after which full deprotection led to the set of free 3-hydroxypiperidines.
- Wijdeven, Marloes A.,Van Delft, Floris L.,Rutjes, Floris P.J.T.
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experimental part
p. 5623 - 5636
(2010/10/02)
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- Stereoselective route towards 2,5-disubstituted piperidine alkaloids. Synthesis of (+)-pseudoconhydrine and (±)-epi-pseudoconhydrine
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This paper describes a new general approach towards functionalized piperidine alkaloids, based on the stereo- and regioselective palladium(0)- catalyzed nucleophilic ring-opening of vinyl epoxides by nitrogen nucleophiles. The latter reaction provides acc
- L?fstedt, Joakim,Pettersson-Fasth, Helena,B?ckvall, Jan-E.
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p. 2225 - 2230
(2007/10/03)
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- 1,4-asymmetric induction in palladium(II)-catalyzed intramolecular N-alkylation reaction. Construction of 2-functionalized 5-hydroxypiperidine
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Palladium(II)-catalyzed cyclization of optically active urethanes containing an allylic alcohol moiety was examined. Efficient 1,4-asymmetric induction was found in this reaction. The cycloadducts were converted to pseudoconhydrine.
- Hirai, Yoshiro,Shibuya, Kaori,Fukuda, Yoko,Yokoyama, Hajime,Yamaguchi, Seiji
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p. 221 - 222
(2007/10/03)
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- A SHORT AND PRACTICAL SYNTHESIS OF (+)-PSEUDOCONHYDRINE AND (+)-N-METHYLPSEUDOCONHYDRINE VIA OSMIUM CATALYZED ASYMMETRIC DIHYDROXYLATION
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A short and practical synthesis of (+)-pseudoconhydrine (1) and (+)-N-methylpseudoconhydrine (2) has been achieved by starting with asymmetric dihydroxylation of the α-amino acid derived N-alkenylurethane (3).
- Takahata, Hiroki,Inose, Kumiko,Momose, Takefumi
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p. 269 - 272
(2007/10/02)
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- ACETOXYLATION OF PIPERIDINE DERIVATIVES AT THE 3-POSITION. STEREOSELECTIVE SYNTHESIS OF PSEUDOCONHYDRINE AND N-METHYLPSEUDOCONHYDRINE
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Anodic oxidation of N-methoxycarbonylpipridine derivatives in AcOH gave 2,3-diacetoxylated products, which were shown to be useful intermediates for the stereoselective synthesis of 3-hydroxypiperidine derivatives including pseudoconhydrine and N-methylpseudoconhydrine, the Conium alcaloids.
- Shono, Tatsuya,Matsumura, Yoshihiro,Onomura, Osamu,Kanazawa, Takenobu,Habuka, Masahiro
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p. 1101 - 1104
(2007/10/02)
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