Chiral Phosphaalkene−Oxazoline Ligands for the Palladium-Catalyzed Asymmetric Allylic Alkylation
作者:Julien Dugal-Tessier、Gregory R. Dake、Derek P. Gates
DOI:10.1021/ol1020652
日期:2010.10.15
Enantioselective catalysis in moderate to excellent yields and ee’s has been accomplished using a phosphaalkene-based ligand system. Specifically, the palladium-catalyzedallylicalkylation of 1,3-diphenyl-2-propenyl acetate using a chiral P(sp2),N(sp2) ligand proceeds with a variety of malonate nucleophiles in 73−95% yield (79−92% ee).
An enantioselective synthesis of allenes through palladium-catalyzed asymmetric allylicalkylation using a chiral diaminophosphine oxide is described. The asymmetric allylicalkylations proceeded in the presence of a catalytic amount of lithium acetate at 4 °C, affording the chiral allenes in excellent yield with up to 99% ee.
Carbofunctionalization of Terminal Alkynes via Rhodium Catalysis Enabling Formations of Four Different Bonds
作者:Dae-Kwon Kim、Minjung Keum、Heekyung Yun、Insu Kim、Jung Min Joo、Chulbom Lee
DOI:10.1021/acs.orglett.3c00341
日期:2023.3.31
disubstituted rhodium vinylidene complex is generated upon C–C bond formation at the terminal alkyne with tethered electrophiles such as alkyl halides, aldehydes, imines, and Michael acceptors. Subsequent intermolecular transfer oxygenation of the rhodium vinylidene with pyridine N-oxide generates a rhodium-complexed ketene intermediate that reacts with a variety of heteroatom nucleophiles to give rise to cyclic