Synthesis and Characterization of Chiral Oxazolidine-2-selones: A General One-Step Procedure from Readily Available Oxazolines
摘要:
The synthesis of a wide variety of chiral oxazolidine-2-selones from readily available 2-oxazolines has been accomplished in one step with yields ranging from 82 to 98%. A mechanistic investigation of the formation of these selones has indicated the presence of intermediate anions which have been characterized by C-13 and Se-77 NMR spectroscopy. X-ray crystallographic data suggest the chiral selones exists as dimeric pairs or networks linked by unusual selenium hydrogen bonds. These chiral reagents exhibit extraordinary Se-77 chemical shift sensitivity and are useful fdr the detection and quantitation of chirality at remotely disposed chiral centers.
Designing the “Search Pathway” in the Development of a New Class of Highly Efficient Stereoselective Hydrosilylation Catalysts
作者:Vincent César、Stéphane Bellemin-Laponnaz、Hubert Wadepohl、Lutz H. Gade
DOI:10.1002/chem.200500132
日期:2005.4.22
coupling of oxazolines and N-heterocyclic carbenes leads to chelating C,N ancillary ligands for asymmetric catalysis that combine both an "anchor" unit and a stereodirecting element. Reacting various N-substituted imidazoles with 2-bromo-4(S)-tert-butyl- and 2-bromo-4(S)-isopropyloxazoline gave the imidazolium precursors of the stereodirecting ancillary ligands. A library of ten different ligand precursors
Efficient Aerobic Wacker Oxidation of Styrenes Using Palladium Bis(isonitrile) Catalysts
作者:Anu Naik、Liu Meina、Manfred Zabel、Oliver Reiser
DOI:10.1002/chem.200901560
日期:2010.2.1
The palladium‐catalyzed aerobicoxidation of alkenes and especially styrenes (Wackeroxidation) by using chiral pseudo C2‐symmetrical bis(isonitrile) ligands in the absence of further cocatalysts gives rise to methyl ketones in a highly chemoselective manner. The palladiumbis(isonitrile) catalyst was characterized by NMR spectroscopy and X‐ray structure analysis, revealing a dissymmetric coordination
Iron-Catalyzed Highly Enantioselective Hydrogenation of Alkenes
作者:Peng Lu、Xiang Ren、Haofeng Xu、Dongpo Lu、Yufeng Sun、Zhan Lu
DOI:10.1021/jacs.1c04773
日期:2021.8.18
for the first time an iron-catalyzed highlyenantioselectivehydrogenation of minimally functionalized 1,1-disubstituted alkenes to accesschiral alkanes with full conversion and excellent ee. A novel chiral 8-oxazoline iminoquinoline ligand and its iron complex have been designed and synthesized. This protocol is operationally simple by using 1 atm of hydrogen gas and shows good functional group tolerance