Unusual heterochiral crystallization tendency of 3-arylphthalide compounds in non-racemic solution: reinvestigation on asymmetric Ni-catalyzed tandem reaction of substituted o-halobenzaldehydes

Transition Metal-Catalyzed Enantioselective Synthesis of Chiral Five- and Six-Membered Benzo O-heterocycles

Enantiomerically enriched five- and six-membered benzo oxygen heterocycles are privileged architectures in functional organic molecules. Over the last several years, many effective methods have been established to access these compounds. However, comprehensive documents cover updated methodologies still in highly demand. In this review, recent transition metal catalyzed transformations lead to chiral five- and six-membered benzo oxygen heterocycles are presented. The mechanism and chirality transfer or control processes are also discussed in details.

Enantioselective synthesis of 3-aryl-phthalides through a nickel-catalyzed stereoconvergent cross-coupling reaction

A nickel-catalyzed asymmetric Suzuki-Miyaura cross-coupling of racemic 3-bromo-phthalides and arylboronic acids was realized for the synthesis of diverse chiral 3-aryl-phthalides in moderate to excellent reaction yields. The reaction proceeded in a stereoconvergent manner and high enantioselectivities were observed for most examined examples. A number of functional groups like aldehyde, ester and bromide were well tolerated. Heteroaromatic boronic acids were also competent coupling partners in this reaction.

Asymmetric tandem hemiaminal-heterocyclization-aza-Mannich reaction of 2-formylbenzonitriles and amines using chiral phase transfer catalysis: an experimental and theoretical study

The first asymmetric synthesis of 3-amino-substituted isoindolinones was accomplished via cascade hemiaminal-heterocyclization-intramolecular aza-Mannich reaction of amines and 2-formylbenzonitriles using chiral phase transfer conditions (PTC).

Enantioselective synthesis of Amaryllidaceae alkaloids (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine

Cat. on a hot tin roof: Enantioselective catalytic Michael addition of α-cyanoketones to acrylates under bifunctional organocatalysis was used to construct the unique arylic all-carbon quaternary stereocenter, which is synthetically crucial in the chemical synthesis of optically pure cis-aryl hydroindole alkaloids. The protocol offers an asymmetric route to (+)-vittatine, (+)-epi-vittatine, and (+)-buphanisine.

Studies on gas-phase cyclometalations of [ArNi(PPh3)n]+ (n = 1 or 2) by electrospray ionization tandem mass spectrometry

Gas-phase cyclometalation of [ArNi(PPh(3))(n)](+) (n = 1, 2) complexes have been studied by ESI-MS/MS. The electron-donating substituents of aromatic iodides in the para position were found to inhibit the cyclometalation process of losing ArH, while the electron-withdrawing substituents in the para position were found to enhance it. These results indicate that the cyclometalation process of losing ArH is favored by electron-deficient aromatic groups. In addition, the detailed dissociation pathways of the cationic nickel complexes were studied, and among these pathways, the process of aryl-aryl interchange was also found to proceed in ESI-MS/MS.

Nickel-catalyzed asymmetric Ullmann coupling for the synthesis of axially chiral tetra-ortho-substituted biaryl dials

The first example of nickel-catalyzed asymmetric Ullmann coupling of bis-ortho-substituted arylhalides is described. With the chiral BINOL-based monodentate phosphoramidite ligand, the reaction allows atropoenantioselective synthesis of a series of axially chiral tetra-ortho-substituted biaryl dials. By taking advantage on this asymmetric Ullman coupling as a key stereogenic axis-forming reaction, the formal synthesis of (+)-isoschizandrin was accomplished.