(CVSAW), ligand-free Suzukicouplings in aqueousmedia. The reactions were carried out on a mmolar scale with low to ultra-low catalyst loadings. The reactions were driven by heating resulting from the penetration of acoustic energy derived from RF Raleigh waves generated by a piezoelectric chip via a renewable fluid coupling layer. The yields were uniformly high and the reactions could be executed without
Enantioselective Synthesis of Allenes by Catalytic Traceless Petasis Reactions
作者:Yao Jiang、Abdallah B. Diagne、Regan J. Thomson、Scott E. Schaus
DOI:10.1021/jacs.6b11937
日期:2017.2.8
Allenes are useful functional groups in synthesis as a result of their inherent chemical properties and established reactivity patterns. One property of chemical bonding renders 1,3-substituted allenes chiral, making them attractive targets for asymmetric synthesis. While there are many enantioselective methods to synthesize chiral allenes from chiral starting materials, fewer methods exist to directly
Chiral P,N-Ligands Based on Ketopinic Acid in the Asymmetric Heck Reaction
作者:Scott R. Gilbertson、Zice Fu
DOI:10.1021/ol006747b
日期:2001.1.1
[figure: see text] Novel chiral P,N-ligands were synthesized from (1S)-(+)-ketopinic acid using palladium-catalyzedcouplingreaction of a vinyl triflate and either a diarylphosphine or a dialkylphosphine as the key step. Palladium complexes of these ligands are efficient catalysts for asymmetric Heck reaction between aryl or alkenyl triflates and cyclic alkenes. Products were obtained with good to
Chiral Bifunctional Phosphine Ligand Enabling Gold-Catalyzed Asymmetric Isomerization of Alkyne to Allene and Asymmetric Synthesis of 2,5-Dihydrofuran
作者:Xinpeng Cheng、Zhixun Wang、Carlos D. Quintanilla、Liming Zhang
DOI:10.1021/jacs.8b12833
日期:2019.3.6
The asymmetric isomerization of alkyne to allene is the most efficient and the completely atom-economic approach to this class of versatile axial chiral structure. However, the state-of-the-art is limited to tert-butyl alk-3-ynoate substrates that possess requisite acidic propargylic C-H bonds. Reported here is a strategy based on gold catalysis that is enabled by a designed chiral bifunctional bi
C1-symmetric chiral bisphosphine, FcPh-Binap (1), which possesses a single diferrocenylphosphino moiety together with a conventional Ph2P-substituent, was prepared in enantiomericallypure forms. Ligand 1 is sterically less demanding than Fc-Segphos (A), which has two diferrocenylphosphino groups, and showed higher activity than A in the rhodium-catalyzed asymmetric conjugate addition of phenylboronic