Development of new catalytic enantioselective formation of methylenelactam-based N,O-spirocyclic compounds via ring opening-asymmetric reclosure of hydroxylactams
Catalytic enantioselective formation of methylenelactam-based N,O-spirocyclic compounds is developed. Hydroxylactams prepared from N-carbonyl phthalimides and β-amido functionalized allylboronates underwent ring opening-asymmetric reclosure in the presence of catalytic amounts of MgBr2 and a chiral aminophenol to afford the corresponding N,O-spirocyclic compounds in excellent yields and high enantioselectivities
Synthesis and characterization of novel chiral NHC–palladium complexes and their application in copper-free Sonogashira reactions
作者:Longguang Yang、Pei Guan、Pan He、Qian Chen、Changsheng Cao、Yu Peng、Zhan Shi、Guangsheng Pang、Yanhui Shi
DOI:10.1039/c2dt12391f
日期:——
A new series of chiral N-heterocyclic carbene (NHC) palladium complexes were synthesized from a relatively inexpensive amino acid, L-phenylalanine. All these compounds were fully characterized by 1H-NMR, 13C-NMR and elemental analysis. The X-ray molecular structures of two of the complexes were reported. The catalytic activity of the four palladium complexes was successfully tested in the Sonogashira reaction under copper free conditions in air. The palladium complex 3a provided good activity in the Sonogashira coupling reaction.