Rearrangements involving acetylenes

Thron, F.; Verny, Michel; Vessire, R.

doi:10.1002/9780470771563.ch10

Cited by 20 publications

(5 citation statements)

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“…The utility of metal ions in the reaction of alkynes is well known. These reactions include the conversion of alkynes to either aldehydes or ketones in the presence of mercuric ion salts and a number of rearrangement reactions . Mercuric acetate is observed to catalyze the rearrangement of acetylenic thioethers leading to nitrogen and sulfur heterocycles .…”

Section: Introductionmentioning

confidence: 99%

Facile Rearrangements of Alkynylamino Heterocycles with Noble Metal Cations

1996

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A number of 2-(alkynylamino)-substituted heterocycles have been synthesized. These heterocycles rearrange in the presence of silver(I) and gold(I) salts to give novel 2H-pyrimido[2,1-b]benzoxazoles, 2H-pyrimido[2,1-b]benzothiazoles, and a 2H-pyrimido[2,1-b]benzoselenazole. Two of the the 2H-pyrimido[2,1-b]benzoxazoles were isolated in good yield. The kinetics of the silver tetrafluoroborate-catalyzed rearrangements of selected (alkynylamino)benzoxazoles and benzothiazoles have been examined by 1H NMR in CD3CN. Factors affecting the electron densities of the triple bond and of the nitrogen atom in the heterocycle are important in influencing the rate of rearrangement.

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Section: Introductionmentioning

confidence: 99%

Facile Rearrangements of Alkynylamino Heterocycles with Noble Metal Cations

1996

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“…Mechanistic details of the formation of 3-aryl-substituted-6chloroimidazo[2, 1-a]phthalazines are reasonably well understood. It involves the following steps (as shown in Scheme 3): (i) formation of ArPdX (B) through oxidative addition of Pd(0) (A) to ArI; [28] (ii) transmetallation of ArPdI with the Cu salt of (C), generating the alkynyl palladium species (D); (iii) extrusion of Pd(0) to yield the alkyne (E); and (iv) isomerization to the allenic intermediate (F), [29] which then cyclizes to the 3-aryl-substituted-6-chloroimidazo[2, 1-a]phthalazines 4 a-j.…”

Section: Resultsmentioning

confidence: 99%

Sonogashira Reaction: Synthesis of Novel Derivatives of 3‐Aryl‐Substituted 6‐Chloroimidazo[2, 1‐a]phthalazines Catalyzed by Pd‐Cu in Water

2018

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The reaction of 1-chloro-4-propargylaminophthalazine with various aryl halides catalyzed by PdÀCu in the presence of potassium carbonate, as the base, in water leads to the one-pot formation of new derivatives of 3-aryl-substituted-6-chloroimidazo-[2, 1-a]phthalazines in moderate-to-good yields. Their structures are confirmed by IR and NMR spectra as well as elemental analyses. All the compounds prepared are screened in vitro for their anti-bacterial activities. The preliminary results indicate that some target compounds exhibit promising antibacterial potency.

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“…Several methods for cycloalkyne synthesis have been developed. However, problems with allene formation and triple-bond migration have hampered these methodologies. Conversion of cyclic β-keto esters to the corresponding cycloalkynes has proven useful in the synthesis of large-ring acetylenes …”

Section: Introductionmentioning

confidence: 99%

Cyclization Reactions of Coordinated Alkynes in Tungsten(II) Complexes

1997

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Displacement of a CO ligand from [Tp‘(CO)2W{HC⋮CH}][OTf] with iodide leads to the neutral parent acetylene complex Tp‘(CO)(I)W{HC⋮CH} (2). Deprotonation of 2 followed by methylation is regioselective and yields a single isomer of the propyne complex Tp‘(CO)(I)W{HC⋮CCH3} (3). Deprotonation of 3 followed by alkylation with RI (R = Me, I(CH2) n (n = 3−7)) is also regioselective and leads to a single isomer, Tp‘(CO)(I)W{RC⋮CCH3} (4 − 9). Deprotonation of Tp‘(CO)(I)W{I(CH2) n C⋮CCH3} (n = 5 (7), 7 (9)) leads to an η2-allenyl intermediate which undergoes intramolecular alkylation (i.e. endocyclic cyclization) to form Tp‘(CO)(I)W{cyclooctyne} (10) and Tp‘(CO)(I)W{cyclodecyne} (11), respectively. The exocyclic cyclization precursor Tp‘(CO)(I)W{PhC⋮C(CH2)5I} (12) was obtained by deprotonation of the propargyl carbon of Tp‘(CO)(I)W{PhC⋮CCH3} followed by alkylation with I(CH2)4I. The cyclopentyl derivative Tp‘(CO)(I)W{PhC⋮C(cyclopentyl)} was generated by deprotonation of 12 followed by intramolecular alkylation (i.e. exocyclic cyclization). A coordinated cyclodecyne ligand is observed in the X-ray structure of Tp‘(CO)(I)W{cyclodecyne} (11).

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Rearrangements involving acetylenes

Cited by 20 publications

References 0 publications

Facile Rearrangements of Alkynylamino Heterocycles with Noble Metal Cations

Facile Rearrangements of Alkynylamino Heterocycles with Noble Metal Cations

Sonogashira Reaction: Synthesis of Novel Derivatives of 3‐Aryl‐Substituted 6‐Chloroimidazo[2, 1‐a]phthalazines Catalyzed by Pd‐Cu in Water

Cyclization Reactions of Coordinated Alkynes in Tungsten(II) Complexes

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