A cationic palladium(II)/(S)-xyl-Segphos complex catalyzes enantioselective cycloisomerizations of N-alkenyl arylethynylamides leading to axiallychiral 4-aryl-2-pyridones in high yields with high ee values. The present catalysis represents the first enantioselective construction of axialchirality by the transition-metal-catalyzed cycloisomerization.
On the Synthesis of Arylpropiolic Acids and Investigations towards the Formation of Vinyl Chlorides by HCl Addition During Esterification Reactions
作者:Marko Hapke、Karolin Kral、Anke Spannenberg
DOI:10.1055/s-0030-1258399
日期:2011.2
The synthesis protocol for the preparation of different arylpropiolic acids using the Negishi reaction and the addition of HCl to the alkyne moiety of these acids in subsequent esterificationreactions using SOCl2 was examined. alkynes - esterification - additionreactions - vinyl chlorides - Negishi reaction
A long‐awaited asymmetric version of the intramolecularhydroarylation of alkynes to form fused ring systems has been developed. A cationic palladium(II)/(S)‐xyl‐H8‐binap complex was used to catalyze an enantioselective hydroarylation of alkynes at room temperature to furnish axially chiral 4‐aryl 2‐quinolinone derivatives in good yields with good enantioselectivity (see scheme; Bn=benzyl).
Atroposelective Synthesis of Triaryl α‐Pyranones with 1,2‐Diaxes by N‐Heterocyclic Carbene Organocatalysis
作者:Simiao Zhang、Xiaoxue Wang、Li‐Li Han、Jibin Li、Zheng Liang、Donghui Wei、Ding Du
DOI:10.1002/anie.202212005
日期:2022.12.23
The single-step atroposelective construction of triaryl α-pyranones with stereogenic 1,2-diaxes was accomplished by NHC organocatalysis. The structure of the substrates and the catalytic system play a critical role in the success of this protocol. DFT calculations were performed to rationalize the origin of the high stereoselectivity.