Chiral Alkyl Amine Synthesis via Catalytic Enantioselective Hydroalkylation of Enecarbamates
作者:Deyun Qian、Srikrishna Bera、Xile Hu
DOI:10.1021/jacs.0c11630
日期:2021.2.3
Chiral alkyl amines are omnipresent as bioactive molecules and synthetic intermediates. The catalytic and enantioselective synthesis of alkyl amines from readily accessible precursors is challenging. Here we develop a nickel-catalyzed hydroalkylation method to assemble a wide range of chiral alkyl amines from enecarbamates (N-Cbz-protected enamines) and alkyl halides with high regio- and enantioselectivity
Chiral oxazolinylpyridines as ligands for enantioselective palladium catalysed allylic substitution
作者:Giorgio Chelucci、Serenella Medici、Antonio Saba
DOI:10.1016/s0957-4166(97)00425-4
日期:1997.10
Chiral oxazolinylpyridines were prepared and assessed in the enantioselective palladiumcatalysedallylic substitution of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate. Enantioselectivity up to 91% was obtained.
Efficient Synthesis of Bulky 2,2’‐Bipyridine and (
<i>S</i>
)‐Pyridine‐Oxazoline Ligands
作者:Zhipeng Zheng、Patrick J. Walsh
DOI:10.1002/adsc.202001218
日期:2021.2.2
N’‐bidentate ligands can furnish catalysts with enhanced catalytic activity compared to commercially available ligands. Straightforward methods to effectively synthesize a broad range of these ligands, however, are uncommon. In this work, a simple and efficient method is developed for the synthesis of bulky N,N’‐bidentate ligands, including 2,2’‐bipyridines and enantioenriched pyridine‐oxazolines. The
2-Markovnikov hydrosilylation of conjugated dienes with primary silanescatalyzed by a quinoline-oxazoline cobalt complex has been described. This protocol provides an efficient approach to chiral allyl dihydrosilanes with high regioselectivity and enantioselectivity (up to 96% ee). The catalyst system is effective for a wide array of conjugated dienes, including mono- and 1,2-disubstituted dienes with aryl
Chemoselective Oxidation of Polyols with Chiral Palladium Catalysts
作者:Antonio G. De Crisci、Kevin Chung、Allen G. Oliver、Diego Solis-Ibarra、Robert M. Waymouth
DOI:10.1021/om4001549
日期:2013.4.8
Chiral palladium-based catalysts derived from pyridinyl oxazoline (pyOx) ligands catalyze the oxidation of alcohols, including 1,2-diols, triols, and tetraols, with high regio- and chemoselectivity. Screening of various chiral oxazoline-derived ligands for the oxidation of a model diol, 1,2-propanediol (1,2-PD), revealed that the nature of the ligand had a significant influence on the activity and cliemoselectivity for oxidation of vicinal diols. The PyOx ligands containing an a-methyl substituent were the most active for the oxidation of 1,2-PD using benzoquinone as the terminal oxidant. Oxidation of vicinal diols and polyols occurs selectively at the secondary alcohol to afford a-hydroxy ketones in isolated yields of 62-87%. Chemoselective oxidation of meso-erythritol with the chiral [(S)-(alpha-Me(tert-Bu)PyOx)Pd(OAc)](2)[OTf](2) afforded (S)-erthyrulose in 62% yield and 24%