A New General Approach to the Synthesis of Oxygen-Containing Heterocycles by Virtue of Hydroxyl Neighboring Group Participation. The Condensation of Enamines with Salicylaldehydes<sup>1</sup>

Paquette, Leo A.; Stucki, Heinz

doi:10.1021/jo01342a060

Cited by 46 publications

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“…Subsequently, we obtained their Raman 23 (see Exptl.) as well as 13 C-NMR spectra 24 (Table 1), which clearly diagnosed the triple bond (2230-2235 cm -1 , medium; 2290-2295 cm -1 , weak) and the sp carbon atoms (75-86 ppm).…”

Section: Resultsmentioning

confidence: 87%

“…The conversion of the vinylogous lactones 7a,c,d into the corresponding chlorohydrins 8a,c,d proceeded in almost quantitative yield, employing the household sodium In sharp contrast to the heteroannular and homoannular oxabicycloalkenones (2, 7a-d), the phenolic substrates 11 13 , 12-13 14 , and 14 15 failed either to undergo a clean reaction with HOCl or posterior satisfactory ring expansion to the desired chloroketolactones (TLC, IR, 1 H-NMR).…”

Section: Resultsmentioning

confidence: 99%

“…Routine 1 H-NMR spectra, reported in the experimental text were obtained on a Varian EM-390 (90 MHz) instrument as CCl4 solutions, unless noted otherwise. The 13 C spectra of the acetylenic lactones were recorded in CDCl3 either at 300/75 or 200/50 MHz, as shown in the Table 1. Gas chromatographic (GC) analyses were carried out on a Varian Aerograph, Model 1440, using 15% FFAP column (3 mm x 2 m), at 210 to 230 °C, swept with N2 (40 mL/min).…”

Section: Methodsmentioning

confidence: 99%

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Synthesis of medium ring and macrocyclic acetylenic lactones by the ring expansion of oxabicycloalkenones

Mahajan¹,

Resck²

1997

J. Braz. Chem. Soc.

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Lactonas acetilênicas de tamanho médio e macrocíclico 15a-e [6-decin-9-olídeo (15a), 7-undecin-10-olídeo (15b), 8-dodecin-11-olídeo (15c), 12-hexadecin-15-olídeo (15d) e 5-decin-9-olídeo (15e)] foram preparadas a partir de oxabiciclo-alquenonas 7a-d e 2, respectivamente, pela expansão de anel das tosil-hidrazonas 16a-e, efetuada pela reação com N-bromo-succinimida, sob condições rigorosamente controladas. A hidrogenação (Pd-C, H2) completa da ligação tripla forneceu lactonas racêmicas saturadas: 9-decanolídeo (foracantolídeo I, 6, de 15a e 15e), 10-undecanolídeo, 11-dodecanolídeo (di-hidro-recifeiolídeo) e 15-hexadecanolídeo. As tentativas de converter di-hidropironas 7a,d nas respectivas lactonas acetilênicas 15a,d, via cloro-hidrinas 8a,d e/ou clorocetolactonas 9a,d, foram apenas parcialmente bem sucedidas.Medium to macrocyclic acetylenic lactones 15a-e [6-decyn-9-olide (15a), 7-undecyn-10-olide (15b), 8-dodecyn-11-olide (15c), 12-hexadecyn-15-olide (15d), and 5-decyn-9-olide (15e)] were prepared from oxabicycloalkenones 7a-d and 2, respectively, by the ring expansion of their tosylhydrazones 16a-e, carried out by reaction with N-bromosuccinimide, under strictly controlled conditions. Complete hydrogenation (Pd-C, H2) of the triple bond gave the racemic saturated lactones: 9-decanolide (phoracantholide I, 6, from 15a and 15e), 10-undecanolide, 11-dodecanolide (dihydrorecifeiolide), and 15-hexadecanolide. The attempts at the conversion of dihydropyrones 7a,d into the respective acetylenic lactones 15a,d, via chlorohydrins 8a,d and/or chloroketolactones 9a,d, were only partially successful.

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Section: Resultsmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of medium ring and macrocyclic acetylenic lactones by the ring expansion of oxabicycloalkenones

Mahajan¹,

Resck²

1997

J. Braz. Chem. Soc.

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“…-Substituted N-benzylaminoacetaldehyde diethyl acetals (3) were prepared on 0.02-mol amounts from aminoacetal and the appropriate benyaldehydes as described.6•13 The acetals, in ethanol over platinum as formed, were combined with 0.02 mol of the second aldehyde and 6 ml of glacial acetic acid and hydrogenated until hydrogen uptake ceased (8-10 hr). The catalyst (11) R. Quelet, M. Mansouri, and R. Pineau, Compt.…”

Section: Experimental Section12mentioning

confidence: 99%

Synthesis of isoquinolines. XI. Dibenzo[c,f]-1-azabicyclo[3.3.1]nonanes and 4-phenyl-1,2,3,4-tetrahydroisoquinolines

Bobbitt¹,

Shibuya²

1970

J. Org. Chem.

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“…-Isoflavones are highly abundant in the legume family of plants and forage grasses, exhibiting numerous biological activities, such as antimicrobial [1], estrogenic [2], antioxidative, antihemolytic [3], and antigiardial effects [4]. These pharmacological activities have stimulated much interest in the synthesis of isoflavones [5] and 3-alkylbenzopyranones [6].…”

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confidence: 99%

A Novel Synthesis of Isoflavones via Copper(I)‐Catalyzed Intramolecular Cyclization Reaction

Liu

et al. 2011

Helvetica Chimica Acta

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Isoflavone derivatives were synthesized via intramolecular cyclization of 3-(2-bromophenyl)-3-oxopropanal derivatives, using CuI as the catalyst, 2-picolinic acid (¼ pyridine-2-carboxylic acid) as the ligand, K 2 CO 3 as the base, and DMF as the solvent, in up to 96% yield. The synthesis is functional grouptolerant. Some methodologies for the preparation of these isoflavones have been already developed [7 -11]. However, the reported methods suffer from hazardous materials or harsh reaction conditions. Transition metal-catalyzed coupling reactions have emerged as a powerful tool for the formation of CÀC [12] and CÀX [13] (X ¼ N, O, S) bonds. Maiti and Buchwald had successfully developed an efficient and complementary set of Cu-and Pd-based catalyst systems for the selective O-and N-arylation of unprotected amino phenols using aryl halides [14]. Together with our previous efforts [15] to construct heterocycles via CuI-catalyzed intramolecular cyclization reactions, these prompted us to investigate the feasibility of a synthesis strategy featuring a Cucatalyzed cyclization reaction of the 3-(2-bromophenyl)-3-oxo-2-phenylpropanal derivatives (Scheme).

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A New General Approach to the Synthesis of Oxygen-Containing Heterocycles by Virtue of Hydroxyl Neighboring Group Participation. The Condensation of Enamines with Salicylaldehydes¹

Cited by 46 publications

References 0 publications

Synthesis of medium ring and macrocyclic acetylenic lactones by the ring expansion of oxabicycloalkenones

Synthesis of medium ring and macrocyclic acetylenic lactones by the ring expansion of oxabicycloalkenones

Synthesis of isoquinolines. XI. Dibenzo[c,f]-1-azabicyclo[3.3.1]nonanes and 4-phenyl-1,2,3,4-tetrahydroisoquinolines

A Novel Synthesis of Isoflavones via Copper(I)‐Catalyzed Intramolecular Cyclization Reaction

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A New General Approach to the Synthesis of Oxygen-Containing Heterocycles by Virtue of Hydroxyl Neighboring Group Participation. The Condensation of Enamines with Salicylaldehydes1

Cited by 46 publications

References 0 publications

Synthesis of medium ring and macrocyclic acetylenic lactones by the ring expansion of oxabicycloalkenones

Synthesis of medium ring and macrocyclic acetylenic lactones by the ring expansion of oxabicycloalkenones

Synthesis of isoquinolines. XI. Dibenzo[c,f]-1-azabicyclo[3.3.1]nonanes and 4-phenyl-1,2,3,4-tetrahydroisoquinolines

A Novel Synthesis of Isoflavones via Copper(I)‐Catalyzed Intramolecular Cyclization Reaction

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A New General Approach to the Synthesis of Oxygen-Containing Heterocycles by Virtue of Hydroxyl Neighboring Group Participation. The Condensation of Enamines with Salicylaldehydes¹