Novel Single Step Preparation of 2- and 2,3-Substituted 1,3-Dienes

Yurchenko, A. G.; Kyrij, A. B.; Likhotvorik, I. R.; Melnik, N. N.; Zaharzh, P.; Bzhezovski, V. V.; Kushko, Andrii

doi:10.1055/s-1991-26474

Cited by 13 publications

(16 citation statements)

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“…These are the focus of the present work, where we first carefully analyzed the reaction of bulky 1 at 130 °C with DMSM in DMSO with an excess of base (Scheme ). As expected, − , 2-(1-adamantyl)butadiene-1,3 ( 2 ) forms in a 17% yield as the main product together with a mixture of sulfur-containing compounds ( 3 ) similar to those described earlier for cyclic ketones …”

supporting

confidence: 83%

“…For example, the yields of the diolefination (path d ) drop considerably for bulky ketones (to ca. 20% for 1-adamantyl methyl ketone ( 1 , R 1 = H; R 2 = adamantyl). , At the same time the classic Corey-Chaykovsky methylenation of 1 with DMSM, which is known to proceed through the same betaine intermediate, , still occurs through path a readily at room temperature to give the corresponding oxirane in up to 88% yield…”

mentioning

confidence: 94%

“…At elevated temperatures and with excess ylide further ring expansion to oxetanes ( b ) and even to oxolanes ( c ) takes place . At higher temperatures and with excess of base ketones can be transformed directly to 1,3-dienes (diolefination, d ) − as well as to unsaturated sulfoxides ( f ) and sulfides ( e ), whose ratios depend on the amounts of DMSO employed. Steric factors influence the high-temperature reactions (paths d and e ) substantially.…”

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confidence: 99%

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Beyond the Corey Reaction II: Dimethylenation of Sterically Congested Ketones

et al. 2014

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Bulky methyl ketones show significantly decreased reactivities toward the Corey-Chaykovsky methylenation reagent dimethylsulfoxonium methylide (DMSM). The excess of base and temperature increase opens an alternative reaction channel that instead leads to the corresponding cyclopropyl ketones. Computations suggest that the initial reaction step involves the methylene group transfer from DMSM on the ketone enolate followed by the intramolecular cyclization. The key step is associated with a barrier of 22 ± 3 kcal mol(-1) and is driven by exothermic elimination of DMSO.

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confidence: 94%

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confidence: 99%

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Beyond the Corey Reaction II: Dimethylenation of Sterically Congested Ketones

et al. 2014

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“…[36] ; IR (KBr): ν ϭ 1550 (CϭO), 1370 (BϪO), 1170Ϫ1020 cm (29), was isolated by filtration and dried to afford a pale yellow powder 51 (12), 43 (40). Ϫ 1,2-Dimethylenecyclohexane: [42] colourless (1.15 g) consisting of (E)-7b and meso-17 (2:5, 1 H NMR). Repeated liquid, b.p.…”

Section: Methodsmentioning

confidence: 99%

“…We explain this puzzling feature in terms of one or more asymmetrical structures with the double bond in the (Z) configuration and different conformations for the acetyl and benzoyl groups, whose apparent equivalence is hence a matter of the We employed the readily available 1,2-dimethylenecyclo-NMR time scales. Rotation around the bond between a sin-hexane [42] because of its permanently cisoid geometry.…”

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confidence: 99%

Tetraacylethenes as Dienophiles and Hetero Dienes in Two-Step Diels–Alder Reactions

Quast¹,

Seefelder

Ivanova

et al. 1999

Eur. J. Org. Chem.

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Oxidation with barium manganate of the enol of tetraacetylethane (10) affords tetraacetylethylene (7a) in good yield. Treatment of the 1,3‐diketones 15a and b with iodosobenzene in the presence of boron trifluoride does not result in oxidative coupling yielding 10 and diacetyldibenzoylethane 17, respectively, as has been reported by Moriarty et al. Instead the known difluoroborylenolates 16 are formed. Oxidative coupling of the sodium enolate of 15b with iodine affords the meso‐tetraketone meso‐17 and diacetyldibenzoylethylene (E)‐7b besides small amounts of rac‐17 and the bisenol 19. In the presence of 1,4‐diazabicyclo[2.2.2]octane, meso‐17 and 19 tautomerise yielding identical equilibrium mixtures of meso‐17, rac‐17, and 19 (26:29:45). Dehydrogenation with 5,6‐dichloro‐2,3‐dicyanobenzoquinone of meso‐17 yields (E)‐7b and an isomer (77:23) which was assigned structure (Z)‐7b on the basis of spectroscopic evidence. – Tetraacetylethylene (7a) reacts with 1,2‐dimethylenecyclohexane to afford two different [4+2]cycloadducts, viz. the spirocyclic dihydropyran 25 (30 %) and the tetraacetyloctalin 27. Whereas the latter is stable, the former isomerises to the latter on heating. Formation of both [4+2]cycloadducts and the isomerisation 25 → 27 are interpreted by invoking the zwitterion 26 as common intermediate. Monoolefines that cannot generate stable carbenium ions don't give [4+2]cycloadducts with 7a. In contrast, α‐methylstyrene yields the oxa Diels–Alder product 30. The structures of (E)‐7b, 19, 25, and 27 are established by X‐ray diffraction analyses.

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Sodium Methylsulfinylmethylide

Harmata

2001

Encyclopedia of Reagents for Organic Synthesis

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Novel Single Step Preparation of 2- and 2,3-Substituted 1,3-Dienes

Cited by 13 publications

References 0 publications

Beyond the Corey Reaction II: Dimethylenation of Sterically Congested Ketones

Beyond the Corey Reaction II: Dimethylenation of Sterically Congested Ketones

Tetraacylethenes as Dienophiles and Hetero Dienes in Two-Step Diels–Alder Reactions

Sodium Methylsulfinylmethylide

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