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.

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.

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.

Gold Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Reaction Pathways to Access 1,3-Aminoalcohols, 3-Hydroxyketones or 3-Aminoketones

2018 ◽  
Author(s):  
Victor Laserna ◽  
Tom Sheppard
Keyword(s):  
Gold Catalysis ◽  
Reaction Pathways ◽  
High Yield ◽  
Reaction Conditions ◽  
Propargylic Alcohols ◽  
Catalytic Quantity ◽  
Selective Formation ◽  
General Method

A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. Firstly, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxy imines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-aminoalcohols with high syn seletivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway.<br>

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