160191-64-0Relevant articles and documents
Chiral alpha-amido aldehyde and preparation method thereof
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, (2020/12/29)
The invention relates to chiral alpha-amido aldehyde and a preparation method thereof. The method comprises the following steps that alpha-dehydroamido aldehyde shown in the following general formula(1) and hydrogen carry out a reduction reaction in an organic solvent under the catalytic action of a diphosphine-rhodium complex, and a chiral alpha-amido aldehyde compound shown in the following general formula (2) is obtained. The synthetic route adopts an asymmetric catalytic hydrogenation method, the process is simple, efficient and green, and the method is very suitable for industrial mass production. The product chiral amido aldehyde can be further derived into a chiral ligand and a chiral drug intermediate.
Chemo- and Enantioselective Hydrogenation of α-Formyl Enamides: An Efficient Access to Chiral α-Amido Aldehydes
Zhang, Jian,Jia, Jia,Zeng, Xincheng,Wang, Yuanhao,Zhang, Zhenfeng,Gridnev, Ilya D.,Zhang, Wanbin
, p. 11505 - 11512 (2019/07/17)
In order to effectively synthesize chiral α-amino aldehydes, which have a wide range of potential applications in organic synthesis and medicinal chemistry, a highly chemo- and enantioselective hydrogenation of α-formyl enamides has been developed, catalyzed by a rhodium complex of a P-stereogenic bisphosphine ligand. Under different hydrogen pressures, the chiral α-amido aldehydes and β-amido alcohols were obtained in high yields (97–99 %) and with excellent chemo- and enantioselectivities (up to >99.9 % ee). The hydrogenation can be carried out on a gram scale and with a high substrate/catalyst ratio (up to 20 000 S/C), and the hydrogenated products were further converted into several important chiral products. Computations of the catalytic cycle gave a clear description for the R/S pathways, provided a reasonable explanation for the enantioselectivity, and revealed several other specific features.
Enantioselective Cyclopropanation of Allylic Alcohols. The Effect of Zinc Iodide
Denmark, Scott E.,O'Connor, Stephen P.
, p. 3375 - 3389 (2007/10/03)
The effect of zinc iodide on the catalytic, enantioselective cyclopropanation of aliylic alcohols is examined with bis(iodomethyl)zinc as the reagent and bis-methanesulfonamide 7 as the catalyst. Significant rate enhancement was observed when 1 equiv of zinc iodide was present, but more importantly, the enantiomeric excess of the product cyclopropane increased from 80% to 89% for the substrate cinnamyl alcohol. Reaction studies and spectroscopic investigations show that this remarkable influence is the result of reagent modification via a Schlenk equilibrium that produces the more reactive and selective species (iodomethyl)zinc iodide.
Preparation of Chiral Bisoxazolines: Observations on the Effect of substituents
Denmark, Scott E.,Nakajima, Norijuki,Nicaise, Olivier J.-C.,Faucher, Anne-Marie,Edwards, James P.
, p. 4884 - 4892 (2007/10/02)
A series of enantiomerically pure 4-substituted bisoxazolines 1a-f, 2c, and 2e was prepared from naturally derived or synthetic amino alcohols and malonyl dichloride derivatives.The formation of the bisoxazolines was accomplished in two stages: (1) preparation of the bis-amides of the malonyl derivatives with the amino alcohols and (2) cyclization of the hydroxy amides 4 by either of two general protocols; (1) heating with thionyl chloride in toluene or (2) formation of the bismesylate and then heating with aqueous or alcoholic base.The latter procedure was found to be more reliable especially for bisoxazolines with bulky substitutents at C(4).The C(4) trityl-substituted hydroxy amide 4f produced the bis(acylaziridine) 10 by cyclization on the nitrogen atom using KOH/MeOH, but afforded the desired bisoxazoline 1f by the action of SOCl2/Et3N.The synthesis of the non-naturally derived amino alcohols using the Evans asymmetric azidation procedure is also described.
