1,6-Hydroolefination and Cascade Cyclization of p-Quinone Methides with Styrenes: Total Synthesis of (±)-Isopaucifloral F.

A Lewis acid-catalyzed intermolecular 1,6-hydroolefination of p-quinone methides with styrenes leading to vinyl diarylmethanes and indenes has been developed. This protocol was also elaborated to the total synthesis of (±)-isopaucifloral F. Besides, interestingly, the reaction between 2-alkynylated p-quinone methides and styrenes provided a straightforward access to dihydrobenzo[ a]fluorene derivatives in one pot with 100% atom-economy.

Tandem One-Pot Approach To Access 1,2,3-Triazole-fused Isoindolines through Cu-Catalyzed 1,6-Conjugate Addition of Me3SiN3 to p-Quinone Methides followed by Intramolecular Click Cycloaddition.

A Cu-catalyzed one-pot approach has been developed for the synthesis of 1,2,3-triazole-fused tricyclic heterocycles. This tandem approach actually involves the 1,6-conjugate addition of Me3SiN3 to o-alkynylated p-quinone methides followed by an intramolecular [3+2]-cycloaddition reaction. This protocol allowed us to access a wide range of 1,2,3-trazole-fused isoindoline derivatives in moderate to good yields.

Exploring Gold Catalysis in a 1,6-Conjugate Addition/Domino Electrophilic Cyclization Cascade: Synthesis of Cyclohepta[ b]indoles.

An effective method for the construction of the structurally complex fused cyclohepta[ b]indole core has been developed through an intermolecular 1,6-conjugate addition of indoles to 2-alkynyl p-quinone methides followed by an intramolecular electrophilic cyclization under oxophilic and alkynophilic gold catalysis.

1,6-Conjugate addition of zinc alkyls to para-quinone methides in a continuous-flow microreactor.

An efficient method for the synthesis of alkyl diarylmethanes through the 1,6-conjugate addition of dialkylzinc reagents to para-quinone methides (p-QMs) has been developed under continuous flow conditions using a microreactor. This protocol allows to access unsymmetrical alkyl diarylmethanes in moderate to excellent yields using a wide range of p-QMs and dialkylzinc reagents. Interestingly, this transformation worked well without the requirement of a catalyst.

A room-temperature protocol to access isoquinolines through Ag(I) catalysed annulation of o-(1-alkynyl)arylaldehydes and ketones with NH4OAc: elaboration to berberine and palmatine.

An efficient and mild protocol for the direct construction of aryl- and alkyl-substituted isoquinolines has been realized through silver nitrate catalyzed aromatic annulation of o-(1-alkynyl)arylaldehydes and ketones with ammonium acetate. The salient feature of this methodology is that this annulation could be effected at room temperature leading to a wide range of isoquinoline derivatives in good to excellent yields. Additionally, this approach has been employed to the synthesis of biologically important isoquinoline alkaloids such as berberine and palmatine.