Reactions of lead(IV). Part XXVIII. Oxidative coupling of methylsubstituted benzenoid compounds: formation of biaryls and diarylmethanes in trifluoroacetic acid

1973 ◽  
pp. 325 ◽  
Author(s):  
Richard O. C. Norman ◽  
C. Barry Thomas ◽  
John S. Willson
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling

Oxidative Coupling of Lignans. III. Non-Phenolic Oxidative Coupling of Deoxypodorhizon and Related Compounds

1988 ◽  
Vol 41 (6) ◽  
pp. 897 ◽  
Author(s):  
RC Cambie ◽  
PA Craw ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Phenolic Substances ◽  
Related Compounds

Oxidative coupling of deoxypodorhizon (4) with thallium(III) oxide and trifluoroacetic acid may be controlled to give either deoxyisopodophyllotoxin (14) or isostegane (16). These results and those with related non- phenolic substances indicate that the aromatic substituents of the parent diarylbutane play an important role in determining the outcome of oxidative coupling.

Access to Biphenyls by Palladium-Catalyzed Oxidative Coupling of Phenyl Carbamates and Phenols

Synthesis ◽  
2019 ◽  
Vol 51 (16) ◽  
pp. 3060-3076 ◽  
Author(s):  
Nadina Truchan ◽  
Christian Jandl ◽  
Alexander Pöthig ◽  
Stefan Breitenlechner ◽  
Thorsten Bach
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Phenyl Ring ◽  
Cross Coupling ◽  
Ortho Position ◽  
Phenyl Substituent ◽  
Steric Factors ◽  
Palladium Catalyzed ◽  
Carbamate Group

The oxidative cross-coupling of phenols (3 equiv) to various substituted phenyl N,N-diethylcarbamates was explored with a variety of substrates. Pd(OAc)2 was employed as the catalyst (20 mol%) and K2S2O8 as the stoichiometric oxidant in trifluoroacetic acid as the solvent (50 °C, 2 h). Carbamates without or with a substituent on the phenyl ring (Me, Ph, Cl, OMe) underwent the reaction unless the phenyl substituent was too strongly electron withdrawing (CN). Cross-coupling occurred exclusively in the ortho position relative to the carbamate group. The regioselectivity at the phenol (ortho or para to hydroxy) was mainly determined by steric factors. Yields up to 60–70% were achieved for specific carbamate/phenol combinations.

Gold-Catalysis: Reactions of Organogold Compounds with Electrophiles

2010 ◽  
Vol 63 (12) ◽  
pp. 1619 ◽  
Author(s):  
A. Stephen K. Hashmi ◽  
Tanuja Dondeti Ramamurthi ◽  
Matthew H. Todd ◽  
Althea S.-K. Tsang ◽  
Katharina Graf
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Gold Catalysis ◽  
Halogenated Compounds

Different arylgold(i), one alkynylgold(i), and one vinylgold(i) triphenylphosphane complexes were subjected to electrophilic halogenation reagents. With N-chlorosuccinimid, N-bromosuccinimid, and N-iodosuccinimid as well as the Barluenga reagent, selectively halogenated compounds were obtained. Trifluoroacetic acid, as a source of protons, leads to a clean protodeauration. With N-fluorobenzenesulfonimide or Selectfluor, exclusively a homocoupling was observed. For the precursor of the vinylgold(i) complex, a similar oxidative coupling could be induced by gold(iii) chloride. Reactions with silicon or tin electrophiles failed.

Synthesis and structure of a stegane from dimethylmatairesinol

1984 ◽  
Vol 37 (8) ◽  
pp. 1775 ◽  
Author(s):  
RC Cambie ◽  
GR Clark ◽  
PA Craw ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
High Yield ◽  
X Ray Diffraction ◽  
X Ray

Oxidative coupling of dimethylmatairesinol with thallium tristrifluoroacetate (prepared in situ from thallium(III) oxide and trifluoroacetic acid) and boron trifluoride etherate gives a high yield of an isostegane which has been isomerized thermally to a stegane. Stereochemical assignments have been confirmed by X-ray diffraction studies.

Intramolecular Oxidative Coupling of Aromatic Compounds. VI. An Efficient Synthesis of Some Dibenzocyclooctene Lignans

1994 ◽  
Vol 47 (5) ◽  
pp. 937 ◽  
Author(s):  
AR Carroll ◽  
WC Taylor
Keyword(s):  
Trans Isomer ◽  
Trifluoroacetic Acid ◽  
Aromatic Compounds ◽  
Oxidative Coupling ◽  
Good Yield ◽  
Reductive Coupling ◽  
Efficient Synthesis

The 1,4-diaryl-2,3-dimethylbutanes (4) and (5) were readily prepared by reductive coupling of an arylacetone precursor followed by hydrogenation. Intramolecular oxidative coupling (dichlorodicyanobenzoquinone/trifluoroacetic acid) gave dibenzocyclooctene derivatives in good yield. (�)-Deoxyschizandrin and the corresponding trans isomer, existing in two distinct conformations, were prepared.

Oxidative Coupling of Lignans. II. Non-Phenolic Coupling of Diarylbutane Lignans Related to Matairesinol Dimethyl Ether

1988 ◽  
Vol 41 (3) ◽  
pp. 305 ◽  
Author(s):  
JS Buckleton ◽  
RC Cambie ◽  
GR Clark ◽  
PA Craw ◽  
CEF Rickard ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Trifluoroacetic Acid ◽  
Oxidative Coupling ◽  
X Ray ◽  
X Ray Crystallography

The non- phenolic oxidative coupling of some diarylbutane lignans related to matairesinol dimethyl ether (1) has been investigated. Coupling with a thallium(III) oxidant, prepared in situ from thallium(III) oxide and trifluoroacetic acid, converts these lignans efficiently into either dibenzocyclooctadiene or aryltetralin lignans. The dibenzocyclooctadiene lignan (5) prepared from oxidative coupling of matairesinol dimethyl ether has been converted into compound (26) which has significant in vitro antileukaemic activity. The structure of the isostegane (27) formed by oxidative coupling of dimethylbutane (14) has been confirmed by X-ray crystallography.

Formation and Trapping of the Thermodynamically Unfavoured Inverted-Hemicucurbit[6]uril

2019 ◽  
Author(s):  
Elena Prigorchenko ◽  
Sandra Kaabel ◽  
Triin Narva ◽  
Anastassia Baškir ◽  
Maria Fomitšenko ◽  
...  
Keyword(s):  
Complex Formation ◽  
Combinatorial Chemistry ◽  
Trifluoroacetic Acid ◽  
Chloride Anion ◽  
Binding Affinities ◽  
Dynamic Covalent Chemistry ◽  
Reaction Selectivity ◽  
Low Concentration ◽  
Dynamic Combinatorial Chemistry ◽  
First Time

Amplification of a thermodynamically unfavoured macrocyclic product through the directed shift of the equilibrium between dynamic covalent chemistry library members is difficult to achieve. We show for the first time that during condensation of formaldehyde and <i>cis</i>-<i>N,N'</i>-cyclohexa-1,2-diylurea formation of <i>inverted-cis</i>-cyclohexanohemicucurbit[6]uril (<i>i-cis</i>-cycHC[6]) can be induced at the expense of thermodynamically favoured <i>cis</i>-cyclohexanohemicucurbit[6]uril (<i>cis</i>-cycHC[6]). The formation of <i>i-cis-</i>cycHC[6] is enhanced in low concentration of the templating chloride anion and suppressed in excess of this template. We found that reaction selectivity is governed by the solution-based template-aided dynamic combinatorial chemistry and continuous removal of the formed cycHC[6] macrocycles from the equilibrating solution by precipitation. Notably, the <i>i-cis</i>-cycHC[6] was isolated with 33% yield. Different binding affinities of three diastereomeric <i>i-cis</i>-, <i>cis</i>-cycHC[6] and their chiral isomer (<i>R,R</i>)-cycHC[6] for trifluoroacetic acid demonstrate the influence of macrocycle geometry on complex formation.

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