6706-92-9Relevant articles and documents
Method for preparing intermediate of chiral vicinal diamine
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Paragraph 0034; 0035; 0038, (2019/01/06)
The invention discloses a method for preparing an intermediate of chiral vicinal diamine. The method comprises the following steps: adding a compound IV into a solvent, stirring the compound IV and the solvent in an ice water bath, adding an initiator into the obtained reaction system, adding a reducing agent into the reaction system in batches, heating the reaction system to 20-80 DEG C, and stirring the reaction system; and extracting the reaction system after the reaction is completed, drying the obtained organic phase, filtering the dried organic phase, and performing rotary drying to obtain a compound V that is the intermediate. The preparation method of the invention has the advantages of simplicity and mild reaction conditions, and can be widely applied to industrial production.
Practical and theoretical aspects of Wacker oxidation of tolanophanes: Synthesis and characterization of novel diketonic cyclophanes
Darabi, Hossein Reza,Rastgar, Saeed,Khatamifar, Ehsan,Aghapoor, Kioumars,Sayahi, Hani,Firouzi, Rohoullah
, (2017/09/30)
Novel cyclophanes having 1,2-diketones 2a–c were synthesized by Wacker oxidation of the corresponding tolanophanes 1a–c having various alkyl chain lengths (n?=?2–4). Among them, tolanophane 1a with the shortest alkyl chain length (n?=?2) having more strained alkyne shows the lowest product selectivity even lower than that of acyclic analogues at various reaction temperatures. In contrast, the oxidation of tolanophane 1b (n?=?3) is clean with the highest activity and selectivity of 2b. Theoretical calculations confirm the experimental data. Based on ab initio calculations, the critical step of the reaction pathway is the interaction of oxygen atoms of 1 (in the absence of H2O) with Pd ion of intermediate [PdCl3(1)]? to give [PdCl2(1)] which keeps Pd ion close to the alkyne bond. This step is not observed computationally for 1a because the positions of the oxygen atoms are outside of its central part. This is in good agreement with almost no activity of 1a at room temperature to prove its rigid structure preventing the O…Pd interaction. Nevertheless, the alkyne…Pd interaction of 1b is not detected by NMR measurements which may be due to its too slow interaction at room temperature (35% after 24?h); however, this confirms ab initio calculation data that the preferred coordinating site is oxygen in the reaction pathway. In contrast, cyclic voltammetry measurements distinguish a different behaviour for the palladium complexation of 1. In general, it is found that the stereochemistry of tolanophanes rather than distortion of alkyne bond plays the critical role in the oxidation. The products are new and their structures were characterized.
Highly efficient asymmetric hydrogenation of cyano-substituted acrylate esters for synthesis of chiral γ-lactams and amino acids
Kong, Duanyang,Li, Meina,Wang, Rui,Zi, Guofu,Hou, Guohua
supporting information, p. 1216 - 1220 (2016/02/03)
A highly efficient and enantioselective synthesis of γ-lactams and γ-amino acids by Rh-catalyzed asymmetric hydrogenation has been developed. Using the Rh-(S,S)-f-spiroPhos complex, under mild conditions a wide range of 3-cyano acrylate esters including both E and Z-isomers and β-cyano-α-aryl-α,β-unsaturated ketones were first hydrogenated with excellent enantioselectivities (up to 98% ee) and high turnover numbers (TON up to 10 000).
