Synthesis of tetrasubstituted cyclopropenes and medium to large carbocyclic alkenes by the intramolecular reductive coupling of diketones with titanium trichloride-lithium aluminum hydride

Baumstark, Alfons L.; Mccloskey, C. J.; Witt, Kay E.

doi:10.1021/jo00412a046

Cited by 49 publications

(10 citation statements)

References 2 publications

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“…[1][2][3] One of the most important applications for the titanium-induced coupling reaction lies in the fact that the intramolecular coupling of dicarbonyl compounds can lead to the formation of cycloalkenes. 4,5 However, in spite of numerous examples concerning the synthesis of cycloalkenes using low-valent titanium reagents, there are few examples of the preparation of 1,2-diheteroarylcycloalkenes. 6 Recently much effort has been devoted to the development of new photochromic compounds, due to their potential use in optical data storage media and other applications.…”

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confidence: 99%

Facile Synthesis of Novel Photochromic 1,2-Diheteroaryl-Substituted Cycloalkenes by Titanium-Induced Intramolecular Coupling Reaction

Huang¹,

Xu²,

Jin³

et al. 1998

Synthesis

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Intramolecular reductive coupling reaction of a series of diketones 1 and dioxo sulfides 3 induced by a low-valent titanium reagent at reflux in tetrahydrofuran affords 1,2-diheteroarylcycloalkenes 2 and 3,4-diheteroaryl-substituted 2,5-dihydrothiophenes 4 , which show photochromic properties on irradiation with UV and visible light.In recent years, the reductive coupling of carbonyl compounds by using low-valent titanium reagents has been widely investigated and employed in the synthesis of various olefins. 1-3 One of the most important applications for the titanium-induced coupling reaction lies in the fact that the intramolecular coupling of dicarbonyl compounds can lead to the formation of cycloalkenes. 4, 5 However, in spite of numerous examples concerning the synthesis of cycloalkenes using low-valent titanium reagents, there are few examples of the preparation of 1,2-diheteroarylcycloalkenes. 6 Recently much effort has been devoted to the development of new photochromic compounds, due to their potential use in optical data storage media and other applications. Among these compounds, 1,2-diarylethenes possess promising properties for practical use. 7-12 With a view to developing novel photochromic 1,2-diarylethenes, we are particularly interested in the preparation of 1,2-diheteroarylcycloalkenes. Thus, in the course of our synthetic studies, we observed that the intramolecular coupling of 1,5-and 1,6-diketones using low-valent titanium reagent could conveniently produce the desired products. Herein we reported the preliminary results.Starting materials, 1,6-bis(1-alkyl-2-methylindol-3-yl)-hexane-1,6-diones 1a-c and 1,5-bis(1-alkyl-2-methylindol-3-yl)pentane-1,5-diones 1g-i were respectively prepared by treatment of adipoyl and glutaryl dichloride with 2-methylindol-3-ylmagnesium bromide, followed by alkylation under basic conditions. Diketones 1d-f and 1j were readily available by Friedel-Crafts acylation with SnCl 4 as catalyst. Dioxo sulfides 3k,l were accessible by reaction of an α -halo ketone with sodium sulfide in refluxing ethanol.The cycloalkenes 2a-j were obtained in moderate yields by the general procedure described in the experimental section. But using this procedure, only traces of 4k,l were isolated. Improvement of the yield of 4k,l by varying the reaction conditions was attempted; finally adding pyridine into the reaction system proved to be effective in raising yields of 4k,l . All the compounds we obtained are new

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confidence: 99%

Facile Synthesis of Novel Photochromic 1,2-Diheteroaryl-Substituted Cycloalkenes by Titanium-Induced Intramolecular Coupling Reaction

Huang¹,

Xu²,

Jin³

et al. 1998

Synthesis

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“…At this point, an intramolecular pinacol‐type McMurry coupling22a of the carbonyl functionalities present in 4 was envisioned as a promising shortcut to benzooxocene 13 . Unfortunately, reaction of 4 with Ti 0 , which was generated in situ, delivered either a complex reaction mixture (with TiCl 3 and freshly prepared Zn/Cu alloy),22b,22c or the benzooxepine derivative 14 arising from an intramolecular aldol condensation (with TiCl 3 and LiAlH 4 )22d (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Meta-analysis of defunctioning stomas in low anterior resection for rectal cancer Br J Surg (Br J Surg 2009; 96: 462–472)

Nash

2009

British Journal of Surgery

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“…Isolated yields for compounds 4 are given in Table 2. The following known compounds included in Table 2 were characterised by comparison of their chromatographic and spectroscopic data ( 1 H, 13 C NMR, and MS) with those described in the literature: 1,2-diphenyl-1-ethene 4a, 19 1,2-di(4-chlorophenyl)-1-ethene 4b, 21 1,2-bis-[4-(dimethylamino)phenyl]ethene 4k, 22 1,2-di(2-furyl)-1-ethene 4l, 23 2,3-diphenyl-2-butene 4g, 24 2,3-di(2-naphthyl)-2-butene 4m, 21 3,4-dimethyl-1,6-diphenyl-1,3,5-hexatriene 4i, 25 1,2-diphenyl-1-cyclohexene 4h, 26 1,2-divinyl-1-cyclohexene 4n, 27 5,6-dibutyl-5-decene 4o.…”

Section: Methodsmentioning

confidence: 99%

Reductive coupling of carbonyl compounds promoted by cobalt or titanium nanoparticles

Nador¹,

Mascaró²,

Castro³

et al. 2011

Arkivoc

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The reaction of a series of aldehydes and ketones with readily prepared cobalt or titanium nanoparticles, under mild reaction conditions, led to the obtention of different reductive dimerization products depending on the nature of the transition metal used. Cobalt nanoparticles (CoNPs) allowed the selective transformation of the starting carbonyl compounds into vicinal diols, whereas the reaction promoted by titanium nanoparticles (TiNPs) led to the formation of the corresponding alkenes. In this last case, the use of trimethylsilyl chloride (TMSCl) as additive, at 0 ºC, also allowed the obtention of vicinal diols after acidic aqueous work-up.

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Synthesis of tetrasubstituted cyclopropenes and medium to large carbocyclic alkenes by the intramolecular reductive coupling of diketones with titanium trichloride-lithium aluminum hydride

Cited by 49 publications

References 2 publications

Facile Synthesis of Novel Photochromic 1,2-Diheteroaryl-Substituted Cycloalkenes by Titanium-Induced Intramolecular Coupling Reaction

Facile Synthesis of Novel Photochromic 1,2-Diheteroaryl-Substituted Cycloalkenes by Titanium-Induced Intramolecular Coupling Reaction

Meta-analysis of defunctioning stomas in low anterior resection for rectal cancer Br J Surg (Br J Surg 2009; 96: 462–472)

Reductive coupling of carbonyl compounds promoted by cobalt or titanium nanoparticles

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