Synthesis and conformational analysis of two chiral (nonracemic) 4-substituted quinolizidines

McIntosh, John M.; Matassa, Luca

doi:10.1021/jo00254a006

Cited by 32 publications

(6 citation statements)

References 5 publications

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“…Indolizidine skeleton formation was realized by two-step sequences. Treatment of 23 with sodium naphthalenide, generated from sodium and naphthalene in THF, at −65 °C gave the detosylated one, which was exposed to carbon tetrabromide and PPh 3 in the presence of Et 3 N 6j, producing the indolizidine derivative 24 in 57% yield.…”

Section: Resultsmentioning

confidence: 99%

Stereoselective Total Synthesis of (±)-Swainsonine Based on Endo Mode Cyclization

Mukai

Miyazawa

et al. 1998

J. Org. Chem.

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A new stereoselective total synthesis of (+/-)-swainsonine is described. Successive treatment of cis-3,4-epoxy-7-(p-toluenesulfonamido)-1-heptyne with dicobalt octacarbonyl, Lewis acid, and cerium(IV) ammonium nitrate effected stereoselective formation of the trans-2-ethynyl-3-hydroxypiperidine skeleton with retention of configuration at the propynyl center. The piperidine derivative thus prepared was converted into the title compound efficiently.

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Section: Resultsmentioning

confidence: 99%

Stereoselective Total Synthesis of (±)-Swainsonine Based on Endo Mode Cyclization

Mukai

Miyazawa

et al. 1998

J. Org. Chem.

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“…After the successful transformation of alkene 52 to the desired hydroxymethyl compound 54 , we turned to construction of the bridged ring system of the montanine alkaloids. Thus, toluenesulfonamide 54 was deprotected by treatment with sodium naphthalenide at −78 °C to generate secondary amine 58 in 96% yield (Scheme ). Cyclodehydration of amine 58 under Mitsunobu conditions afforded the bridged pentacyclic intermediate 59 (94%).…”

Section: Resultsmentioning

confidence: 99%

Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of Amaryllidaceae Alkaloids

Jin

Weinreb

1997

J. Am. Chem. Soc.

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Enantioselective total syntheses of the pentacyclic 5,11-methanomorphanthridine Amaryllidaceae alkaloids (−)-montanine (1), (−)-coccinine (2), and (−)-pancracine (3) were accomplished using an intramolecular concerted pericyclic allenylsilane imino ene cycloaddition as a key step. These complex natural products were constructed starting from readily available enantiomerically pure epoxy alcohol 15 which was converted to allenylsilane aldehyde 28 via an efficient nine-step sequence. The imine generated from aldehyde 28 and iminophosphorane 47 underwent a stereospecific thermal imino ene reaction to afford key intermediate cis aminoalkyne 49. It was possible to transform this compound via Lindlar hydrogenation followed by an intramolecular Heck reaction to seven-membered ring tetracycle 51. This olefinic intermediate could be functionalized through its epoxide to yield α-hydroxymethyl intermediate 54, and then pentacyclic alcohol 64. Procedures were then developed to convert this material to the enantiomerically pure alkaloids 1−3. A formal enantioselective total synthesis of (−)-brunsvigine (4) was also achieved via triol 72.

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“…2.1.1 Indolizidine 3 and quinolizidine. 4 The preparation of hydroxylated indolizidines was imagined following a scheme where the cyclization step is an intramolecular opening of an epoxide by the piperidine nitrogen.…”

Section: A-substituted Pyrrolidines and Piperidines Included In Compl...mentioning

confidence: 99%

“…An efficient synthesis of unnatural dihydroxyquinolizidine 16 from 1 was reported by McIntosh. 4 Alkylation of the anion of 1 with iodobutanal ethylene ketal (Scheme 7) permitted the preparation of enantiomerically pure (2S)-piperidine derivative 13, which was transformed to allylic alcohol 14 by classical reactions. Sharpless epoxidation of 14 in the presence of (+)-diethyl tartrate (DET) led to epoxide 15 which was cyclized to 16 upon treatment with sodium naphthalenide.…”

Section: A-substituted Pyrrolidines and Piperidines Included In Compl...mentioning

confidence: 99%

Chiral non-racemic N-cyanomethyloxazolidines: the pivotal system of the CN(R,S) method

Husson¹,

Royer²

1999

Chem. Soc. Rev.

189

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Synthesis and conformational analysis of two chiral (nonracemic) 4-substituted quinolizidines

Cited by 32 publications

References 5 publications

Stereoselective Total Synthesis of (±)-Swainsonine Based on Endo Mode Cyclization

Stereoselective Total Synthesis of (±)-Swainsonine Based on Endo Mode Cyclization

Application of a Stereospecific Intramolecular Allenylsilane Imino Ene Reaction to Enantioselective Total Synthesis of the 5,11-Methanomorphanthridine Class of Amaryllidaceae Alkaloids

Chiral non-racemic N-cyanomethyloxazolidines: the pivotal system of the CN(R,S) method

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