Preparation of C2-symmetric bicyclo[2.2.2]octa-2,5-diene ligands and their use for rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids.

[reaction: see text] C2-symmetric bicyclo[2.2.2]octa-2,5-dienes containing benzyl, phenyl, and substituted phenyl groups at 2 and 5 positions were prepared enantiomerically pure by way of bicyclo[2.2.2]octane-2,5-dione as a key intermediate. These chiral diene ligands were successfully applied to rhodium-catalyzed asymmetric 1,4-addition of arylboronic acids to alpha,beta-unsaturated ketones. High enantioselectivity (up to 99% ee) as well as high catalytic activity was observed in the addition to both cyclic and linear substrates.

C2-symmetric bicyclo[3.3.1]nonadiene as a chiral ligand for rhodium-catalyzed asymmetric arylation of N-(4-nitrobenzenesulfonyl)arylimines.

[Reaction: see text] Asymmetric synthesis of diarylmethylamines with high enantioselectivity (95-99% ee) was realized by use of a new C2-symmetric diene ligand, (1R,5R)-2,6-diphenylbicyclo[3.3.1]nona-2,6-diene (Ph-bnd), for the rhodium-catalyzed asymmetric arylation of N-(4-nitrobenzenesulfonyl)arylimines with arylboroxines.

Catalytic asymmetric arylative cyclization of alkynals: phosphine-free rhodium/diene complexes as efficient catalysts.

Catalytic arylative cyclization of alkynals has been developed by the use of phosphine-free rhodium/diene complexes as catalysts. An asymmetric variant of this process has been successfully realized by employing a C2-symmetric chiral bicyclo[2.2.2]octadiene ligand. The rhodium/diene catalyst system is also effective for arylative cyclization of other substrates such as alkynones and enynes, achieving multiple carbon-carbon bond formations in a single step.

C2-symmetric bicyclo[2.2.2]octadienes as chiral ligands: their high performance in rhodium-catalyzed asymmetric arylation of N-tosylarylimines.

Asymmetric synthesis of diarylmethylamines with high enantioselectivity (95-99% ee) was realized by use of a new C2-symmetric diene ligand, (1R,4R)-2,5-diphenylbicyclo[2.2.2]octa-2,5-diene (Ph-bod*), for the rhodium-catalyzed asymmetric arylation of N-tosylarylimines with arylboroxines.

Preparation of an amphiphilic resin-supported BINAP ligand and its use for rhodium-catalyzed asymmetric 1,4-addition of phenylboronic acid in water.

[reaction: see text] The axially chiral bisphosphine ligand, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (binap), was supported on a polystyrene-poly(ethylene glycol) copolymer (PS-PEG) resin and was used successfully for the rhodium-catalyzed asymmetric 1,4-addition of phenylboronic acid to alpha,beta-unsaturated ketones in water.