670234-10-3Relevant academic research and scientific papers
Kinetic resolution of racemic allylic alcoholsviairidium-catalyzed asymmetric hydrogenation: scope, synthetic applications and insight into the origin of selectivity
Wu, Haibo,Margarita, Cristiana,Jongcharoenkamol, Jira,Nolan, Mark D.,Singh, Thishana,Andersson, Pher G.
, p. 1937 - 1943 (2021/02/22)
Asymmetric hydrogenation is one of the most commonly used tools in organic synthesis, whereas, kinetic resolutionviaasymmetric hydrogenation is less developed. Herein, we describe the first iridium catalyzed kinetic resolution of a wide range of trisubstituted secondary and tertiary allylic alcohols. Large selectivity factors were observed in most cases (sup to 211), providing the unreacted starting materials in good yield with high levels of enantiopurity (ee up to >99%). The utility of this method is highlighted in the enantioselective formal synthesis of some bioactive natural products including pumiliotoxin A, inthomycin A and B. DFT studies and a selectivity model concerning the origin of selectivity are presented.
Zinc-Catalyzed Enantioselective Hydrosilylation of Ketones and Imines under Solvent-Free Conditions
Szewczyk, Marcin,Bez?ada, Agata,Mlynarski, Jacek
, p. 3575 - 3579 (2016/12/14)
The zinc acetate promoted asymmetric hydrosilylation of various ketones and imines under solvent-free conditions was examined by using an unprecedented low catalyst loading. Exposure of ketones to 0.05 mol % Zn-based chiral diamine complex in the presence of triethoxysilane afforded enantioenriched alcohols in excellent yields (up to 98 %) and enantioselectivities (up to 97 % ee). This methodology also allowed for the chemoselective 1,2-reduction of α,β-unsaturated ketones and imines.
Enantioselective addition of organozinc reagents to carbonyl compounds catalyzed by a camphor derived chiral γ-amino thiol ligand
Wu, Hsyueh-Liang,Wu, Ping-Yu,Cheng, Ying-Ni,Uang, Biing-Jiun
, p. 2656 - 2665 (2016/05/10)
In this article, the design and synthesis of the chiral camphor derived γ-amino thiol ligand 17 and its application in catalytic enantioselective carbon-carbon forming reactions through the addition of organozinc reagents to carbonyl compounds is described. The catalytic activity and enantioselectivity of ligand 17 is demonstrated in the enantioselective addition of various organozinc reagents to aldehydes and ketoesters, offering the corresponding alcohols in high yields and enantioselectivities. The role of the mercapto group in the highly enantioselective 1,2-addition reaction of organozincs to aldehyde is also discussed.
Enantioselective reduction of ketones and imines catalyzed by (CN-Box)ReV-oxo complexes
Nolin, Kristine A.,Ahn, Richard W.,Kobayashi, Yusuke,Kennedy-Smith, Joshua J.,Toste, F. Dean
supporting information; experimental part, p. 9555 - 9562 (2010/10/03)
The development and application of chiral, non-racemic ReV-oxo complexes to the enantioselective reduction of prochiral ketones is described. In addition to the enantioselective reduction of prochiral ketones, we report the application of these complexes to 1) a tandem Meyer-Schuster rearrangement/reduction to access enantioenriched allylic alcohols and 2) the enantioselective reduction of imines.
Structural features and reactivity of (sparteine)PdCl2: A model for selectivity in the oxidative kinetic resolution of secondary alcohols
Trend, Raissa M.,Stoltz, Brian M.
scheme or table, p. 15957 - 15966 (2009/05/16)
The chiral ligand (-)-sparteine and PdCl2 catalyze the enantioselective oxidation of secondary alcohols to ketones and thus effect a kinetic resolution. The structural features of sparteine that led to the selectivity observed in the reaction were not clear. Substitution experiments with pyridine derivatives and structural studies of the complexes generated were carried out on (sparteine)PdCl2 and indicated that the C1 symmetry of (-)-sparteine is essential to the location of substitution at the metal center. Palladium alkoxides were synthesized from secondary alcohols that are relevant steric models for the kinetic resolution. The solid-state structures of the alkoxides also confirmed the results from the pyridine derivative substitution studies. A model for enantioinduction was developed with C1 symmetry and Cl- as key features. Further studies of the diastereomers of (-)-sparteine, (-)-α-iso- and (+)-β- isosparteine, in the kinetic resolution showed that these C2- symmetric counterparts are inferior ligands in this stereoablative reaction.
