Tf2NH-Catalyzed 1,6-Conjugate Addition of Vinyl Azides with p-Quinone Methides: A Mild and Efficient Method for the Synthesis of β-Bis-Arylamides

Abstract

Tf2NH-catalyzed tandem 1,6-conjugate addition/Schmidt type rearrangement using vinyl azides and p-quinone methides to access a variety of β-bis-arylated amides is reported. The method is quick, efficient, mild, and high yielding with broad substrate scope.

Harnessing Nucleophilicity of Allenol Ester with p-Quinone Methides via Gold Catalysis: Application to the Synthesis of Diarylmethine-Substituted Enones

“…Further Angle and China Raju exquisitely demonstrated Lewis acid catalyzed intramolecular cyclization reaction on p -QMs utilizing terminators such as allyl silanes and β-keto esters appended to p -QMs. Recently our group has also reported acid-catalyzed 1,6-conjugate addition reaction of p -QMs with vinyl azides and butenolides . To the best of our knowledge, the gold-catalyzed activation of alkynes along with p -QMs toward 1,6-conjugate addition has not yet been explored.…”

Unravelling the Nucleophilicity of Butenolides for 1,6-Conjugate Addition to p-Quinone Methides: A Direct Access to Diversely Substituted Butenolide-Derived Diarylmethanes

“…In 2004, Eklund and co-workers elegantly showed the oxidative metabolism of plant lignan hydroxymatairesinol to its corresponding butyrolactone lignins, isohydroxymatairesinol and epi -isohydroxymatairesinol, via a p -QMs intermediate. Recently, our group also reported a Tf 2 NH-catalyzed 1,6-conjugate addition reaction of p -QMs with vinyl azide . In continuation herein, we report a highly efficient and regioselective 1,6-conjugate addition of deconjugated butenolides and silyloxyfurans to p -QMs catalyzed by Lewis acid, leading to a diversely substituted butenolide-derived diarylmethane scaffold.…”

Zn(OTf)2-Catalyzed 1,6-Conjugate Addition of Benzoxazinones to p-Quinone Methides: Access to 3,3-Diaryl-2-(2-oxo-2H-1,4-benzoxazin-3-yl)propanoic Acid Esters

“…The reaction was further examined by switching to various polar protic, nonpolar protic, or halogenated solvents [ethyl acetate, ethanol, methanol, DMF, toluene, chloroform, dichloroethane, and acetonitrile] (entries 12-17), and the results revealed that acetonitrile was superior to the other solvents (entry 17). Next, we examined the effect of the catalyst loading by changing the amount of catalyst from 2 to 20 mol% (entries [18][19][20]. There was no significant change in the yield of product 3, and therefore 2 mol% of Zn(OTf) 2 in appeared ideal for this reaction, as it provided the product in 93% yield (entry 20).…”

“…Anand and co-workers targeted the synthesis of -arylated nitriles and ,-diarylated ketones by using N-heterocyclic carbenes. 16 Li and co-workers reported the synthesis of a organophosphorus compounds 17 and a -bisaryl amide 18 through base-catalyzed 1,6-conjugate additions to p-QMs. The Muthukrishnan group synthesized -arylated nitriles by BF 3 •Et 2 O-catalyzed cyanation of a p-QM by using tert-butyl isocyanide.…”