RESUMO
The first application of 3-methyl-2-vinylindoles in catalytic asymmetric Povarov reactions has been established via the three-component reactions of 3-methyl-2-vinylindoles, aldehydes, and anilines in the presence of chiral phosphoric acid, providing easy access to chiral indole-derived tetrahydroquinolines with three contiguous stereogenic centers at high yields (up to 99%) and with excellent diastereo- and enantioselectivities (all >95:5 dr, up to 96% ee). This mode of catalytic asymmetric three-component reaction offers a step-economic and atom-economic strategy for accessing enantioenriched indole-derived tetrahydroquinolines with structural diversity and complexity.
RESUMO
A regioselective and stereoselective difluoromethylation of enamides with bench-stable and easily accessible difluoromethyltriphenylphosphonium bromide is described. A broad array of synthetically important and geometrically defined ß-difluoromethylated enamides bearing various functional groups are obtained with up to 91% yield.
RESUMO
An efficient and straightforward stereoselective alkylation reaction of enamides using commercially available and easily accessible unactivated alkyl carboxylic acids as alkylating agents is described, giving rise to a diverse array of synthetically important and geometrically defined ß-alkylated enamides bearing primary, secondary, or tertiary alkyl moieties. This transformation also shows excellent functional group tolerance, satisfying atom economy, and operational simplicity.
RESUMO
The first catalytic asymmetric α-arylation of pyrazol-5-ones has been established by using 2-indolylmethanols as direct electrophilic arylation reagents under the cooperative catalysis of Pd(0) and a chiral phosphoric acid, which afforded the α-arylation products of pyrazol-5-ones in generally high yields and good enantioselectivities (up to 99% yield, >99% ee).