A platinum-catalyzed annulation reaction leading to medium-sized rings

Hildebrandt, Dirk; Hüggenberg, Wiebke; Kanthak, Matthias; Plöger, Tobias A.; Müller, Iris M.; Dyker, Gerald

doi:10.1039/b602498j

Cited by 69 publications

(14 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[283][284][285][286][287][288] Huang et al 289 successfully demonstrated the ring-expansion reaction of bicyclic vinylidenecyclopropanes (160) in the presence of titanium chloride (TiCl 4 ) as a Lewis acid catalyst in dichloromethane, providing an efficient method for the synthesis of naphthalenes with annulated carbocycles of various ring sizes (161) in good to excellent yields under mild conditions at room temperature (Scheme 57). [283][284][285][286][287][288] Huang et al 289 successfully demonstrated the ring-expansion reaction of bicyclic vinylidenecyclopropanes (160) in the presence of titanium chloride (TiCl 4 ) as a Lewis acid catalyst in dichloromethane, providing an efficient method for the synthesis of naphthalenes with annulated carbocycles of various ring sizes (161) in good to excellent yields under mild conditions at room temperature (Scheme 57).…”

Section: Ring-expansionmentioning

confidence: 99%

Design for carbon–carbon bond forming reactions under ambient conditions

Brahmachari

2016

RSC Adv.

View full text Add to dashboard Cite

Carbon-carbon (C-C) bond forms the 'backbone' of nearly every organic molecule, and lies at the heart of the chemical sciences! This transformation has always been one of the most useful and fundamental reactions in the development of organic chemistry. Currently, the concept of 'green chemistry' is globally acclaimed and has already advanced quite significantly to come out as a distinct branch of chemical sciences. Among the principles of 'green chemistry', one principle is dedicated to "design of energy efficiency" -that is to develop synthetic strategies that require less/minimum amount of energy to carry out a specific reaction with optimum productivity. And the most effective way-out to save energy is to develop strategies/protocols that are capable enough to carry out the transformations at ambient temperature and pressure! As part of on-going developments on green synthetic strategies, designing for reactions under ambient conditions coupled with other green aspects is, thus, an area of current choice. This review is aimed to offer an up-to-date development on the design of carbon-carbon bond forming protocols to access a wide variety of organic molecules of topical significance under ambient conditions. The account highlights on the brilliant applications of reaction conditions such as the use of solvents or no solvent, catalysts or no catalyst, and the use of green tools like ball-milling, ultrasonication and visible light in achieving the goal! Design for Carbon Carbon Frameworks at Ambient ConditionsN Me Me Me O O COOH Br Br (Graphic for TOC)

show abstract

Section: Ring-expansionmentioning

confidence: 99%

Design for carbon–carbon bond forming reactions under ambient conditions

Brahmachari

2016

RSC Adv.

View full text Add to dashboard Cite

show abstract

“…68 A very efficient de process for the Curtius rearrangement that allows the direct conversion of aromatic carboxylic acids into carbamates and ureas has been developed. A facile synthesis of five membered antiviral azasugars (94), which involves an exo-imino to endo-iminocyclitol rearrangement, has been reported (Scheme 24). The formate serves to activate the carboxylic acids and as a source of nucleophilic alkoxide.…”

Section: Rearrangements Involving Electron-deficient Heteroatomsmentioning

confidence: 99%

“…69 This process is based on the use of various commercially available chloroformates and sodium azide, which presumably generate the corresponding azidoformate. 71 The mechanism of conversion of (91) to (94) shows that the key step is the intramolecular 5-exo-tet ring opening of the epoxide with inversion of configuration at C(4). A cavity-containing metal-ligand assembly has been used as a catalytic host for the 3-aza Cope rearrangement of allyl enammonium cations.…”

Section: Rearrangements Involving Electron-deficient Heteroatomsmentioning

confidence: 99%

“…A key point that emerges is that chelation of the 1,6-diene at various stages in the mechanism plays an important role in determining the regioselectivity of the reaction. 94 A plausible mechanism for the platinum(II)-catalysed annulation reaction shows that the double annulation process most probably proceeds through the benzopyrylium cation (117), which results from the nucleophilic attack of the carbonyl oxygen at the alkyne, activated by the Lewisacidic platinum salt. 92 6-(2-Benzofuryl)purines are readily available via a one-pot Sonogashira coupling-cyclization between 6iodopurine and 2-ethynylphenol.…”

Section: Rearrangement Involving Organometallic Compoundsmentioning

confidence: 99%

See 1 more Smart Citation

Molecular Rearrangements: Part 2. Other Reactions

Brandi

Gensini

2010

Organic Reaction Mechanisms · 2006

View full text Add to dashboard Cite

The formation of α-phenyl-β-halovinyl cation, β-phenyl-α-halovinyl cation, and also the halogen-bridged and the spirocyclic phenyl-bridged cations, as intermediates of protonation of phenylethynyl halides, or of halogen addition to phenylethynes, has been evaluated by DFT at the B3LYP/6-31+G(d) level and, for comparison in representative cases, by B3LYP/6-311++G(d,p). 1 Structural and mechanistic studies of the lithium diisopropylamide (LDA)-mediated anionic Fries rearrangements of aryl carbamates have been described. 2 Substituents at the meta position of the arene (H, OMe, F) and the dialkylamino moiety of the carbamate (Me 2 N, Et 2 N, and i-Pr 2 N) markedly influence the relative rates of ortholithiation and subsequent Fries rearrangement. The mechanism of the Fries rearrangement of aryl formates promoted by boron trichloride has been studied by means of 1 H, 2 H, and 11 B NMR spectroscopy and DFT calculations. 3 After the formation of a 1:1 substrate -Lewis acid adduct, the rearrangement proceeds in two steps, beginning with the cleavage of the ester bond and the release of formyl chloride in situ, which, in turn, acts as a formylating agent, introducing 451

show abstract

“…This was a very unusual reaction in which the insertion of a Pt-carbene species into CÀH b bond formed the corresponding cyclopropanes such as 8. [18] Note that metalcarbenes generally undergo cyclopropanation in the reaction with alkenes. Several conditions were tested to optimize the reaction efficacy.…”

mentioning

confidence: 99%