Synthesis of Desoxydiplodialide D and Phoracantholide I from Dihydroresorcinol

Mahajan, J. R.; Silva, Carlos Roberto da

doi:10.5935/0103-5053.19900019

Cited by 5 publications

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“…The regeneration of the vinylogous lactones 7a,d involves, most probably, the intramolecular (transannular) acylation of the organo-zinc intermediate, in preference to its protonation, as encountered earlier 3 , albeit as a minor process, in our first example outlined in Scheme 1.…”

Section: Resultsmentioning

confidence: 96%

“…The vinylogous lactone 2 was prepared as described earlier 3 . Enamines of 6-8 membered cycloalkanones were obtained according to the known procedure employing azeotropic removal (Dean-Stark) of water 27 Crotonyl chloride was prepared by a slight modification of the method described for the preparation of acriloyl chloride 31 : Thionyl chloride (10 mL, 16.31 g, 137 mmol) was added to a magnetically stirred mixture of crotonic acid (8.6 g, 0.1 mol), sulphur powder (160 mg), cuprous chloride (0.5 g, 5 mmol) and hydroquinone (110 mg, 1 mmol).…”

Section: Methodsmentioning

confidence: 99%

“…Thus, in 1990, we described the preparation of desoxydiplodialide D (5) and phoracantholide I (6) from cyclohexane-1,3-dione 3 (1) by a novel ring expansion of the vinylogous lactone intermediate 2, as illustrated in Scheme 1.…”

Section: Introductionmentioning

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: 96%

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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Multicomponent Reactions of 1,3‐Cyclohexanediones and Formaldehyde in Glycerol: Stabilization of Paraformaldehyde in Glycerol Resulted from using Dimedone as Substrate

Chen

et al. 2010

Adv Synth Catal

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Glycerol has proved to be an effective promoting medium for many multicomponent reactions of 1,3-cyclohexanediones and formaldehyde. Styrenes, amines, 2-naphthol, 4-hydroxy-6-methyl-2-pyrone and 4-hydroxy-1-methyl-2-quinolone could easily react with 1,3-cyclohexanediones and paraformA C H T U N G T R E N N U N G aldehyde in glycerol under catalyst-free conditions to afford a variety of complex skeletons in fair to excellent yields. In these reactions, glycerol not only showed a significant promoting effect on the reaction yields but also endowed the reaction system with many typical properties of green chemistry, such as cheap, renewable, recyclable and biodegradable solvent, good safety and easy separation of product. The promoting effect of glycerol for the three-component reaction of styrene, dimedone and paraformA C H T U N G T R E N N U N G aldehyde could be attributed to a restricted formation of the methylene intermediate in glycerol. During the reaction, a physical shell, which is mainly composed of a by-product generated in the beginning of the reaction, might be formed in the surface of paraformaldehyde and plays a key role in controlling the formation of the intermediate by means of restricting the decomposition of paraformaldehyde.

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Medium ring lactones

Rousseau

1995

Tetrahedron

200

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Synthesis of Desoxydiplodialide D and Phoracantholide I from Dihydroresorcinol

Cited by 5 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

Multicomponent Reactions of 1,3‐Cyclohexanediones and Formaldehyde in Glycerol: Stabilization of Paraformaldehyde in Glycerol Resulted from using Dimedone as Substrate

Medium ring lactones

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