Chiral phosphoric acid catalyzed aminative dearomatization of α-naphthols/Michael addition sequence.

Asymmetric dearomatization reactions have recently emerged as a powerful tool for the rapid build-up of the molecular complexity. Chiral three-dimensional polycyclic molecules bearing contiguous stereogenic centers can be synthesized from readily available planar aromatic feedstocks. Here we report that an intermolecular asymmetric dearomatization reaction of α-naphthols bearing a tethered nucleophile at the C4 position of the naphthol ring is achieved by a chiral phosphoric acid.

Pd(0)-Catalyzed intramolecular arylative dearomatization of β-naphthols.

An efficient Pd(0)-catalyzed intramolecular arylative dearomatization of β-naphthols is described. Using Q-Phos as a ligand, the arylative dearomatization reaction proceeded smoothly affording excellent yields and chemoselectivity even when the catalyst loading was reduced to 0.1 mol%.

Construction of the Benzomesembrine Skeleton: Palladium(0)-Catalyzed Intermolecular Arylative Dearomatization of α-Naphthols and Subsequent Aza-Michael Reaction.

A novel palladium(0)-catalyzed intermolecular arylative dearomatization of α-naphthols and subsequent aza-Michael reaction is described. Two adjacent stereocenters were constructed efficiently through consecutive arylative dearomatization and Michael addition reactions. By utilizing this method, structurally diverse benzomesembrine derivatives were synthesized with excellent yields and chemoselectivity.

Construction of Chiral Tetrahydro-β-Carbolines: Asymmetric Pictet-Spengler Reaction of Indolyl Dihydropyridines.

A highly efficient synthesis of the enantioenriched tetrahydro-β-carbolines was developed by using a chiral phosphoric acid catalyzed Pictet-Spengler reaction of indolyl dihydropyridines. The reaction proceeds under mild reaction conditions to afford the desired chiral tetrahydro-β-carbolines in good to excellent yields (up to 96 %) and high enantioselectivities (up to 99 % ee). With this method, a formal synthesis of tangutorine and a total synthesis of deplancheine were achieved in a highly efficient manner.

Iridium-Catalyzed Intermolecular Asymmetric Dearomatization of β-Naphthols with Allyl Alcohols or Allyl Ethers.

An Ir-catalyzed intermolecular asymmetric dearomatization reaction of β-naphthols with allyl alcohols or allyl ethers was developed. When an iridium catalyst generated from [Ir(COD)Cl] (COD=cyclooctadiene) and a chiral P/olefin ligand is employed, highly functionalized β-naphthalenone compounds bearing an all-carbon-substituted quaternary chiral center were obtained in up to 92 % yield and 98 % ee. The direct utilization of allyl alcohols as electrophiles represents an improvement from the viewpoint of atom economy.

Palladium(0)-Catalyzed Intermolecular Arylative Dearomatization of β-Naphthols.

The first Pd -catalyzed intermolecular arylative dearomatization of β-naphthols with aryl halides is described. It was found that Q-Phos could facilitate the palladium-catalyzed cross-coupling-type dearomatization of β-naphthols, while avoiding O-arylation, to construct 2-naphthalenones in excellent yields and with high chemoselectivity.

Construction of spirocarbocycles gold-catalyzed intramolecular dearomatization of naphthols.

A highly efficient, gold-catalyzed intramolecular dearomatization reaction of naphthols 5- cyclization is described. This facile and direct approach furnishes spirocarbocycles in excellent yields under mild conditions.

Construction of erythrinane skeleton via Pd(0)-catalyzed intramolecular dearomatization of para-aminophenols.

A novel Pd(0)-catalyzed intramolecular arylative dearomatization of para-aminophenol derivatives is described. In the presence of 1.25 mol % [Pd(C3H5)Cl]2 and 3.