Pyridine synthesis from oximes and alkynesviarhodium(<scp>iii</scp>) catalysis: Cp* and Cp<sup>t</sup>provide complementary selectivity
作者:Todd K. Hyster、Tomislav Rovis
DOI:10.1039/c1cc15248c
日期:——
The synthesis of pyridines from readily available α,β-unsaturated oximes and alkynes under mild conditions and low temperatures using Rh(III) catalysis has been developed. It was found that the use of sterically different ligands allows for complementary selectivities to be achieved.
beta-unsaturated oximes and internalalkynes has been developed using [Cp*RhCl2](2)-CsOPiv as the catalyst system. The present transformation is carried out by a redox-neutral sequence of vinylic C-H rhodation, alkyne insertion, and C-N bond formation of the putative vinyl rhodium intermediate with the oxime nitrogen, where the N-Obond of oxime derivatives could work as an internaloxidant to maintain the catalytic
使用 [Cp*RhCl2](2)-CsOPiv 作为催化剂体系开发了一种从 α、β-不饱和肟和内部炔烃合成高度取代的吡啶的方法。目前的转化是通过乙烯基 CH 化、炔插入和 CN 键形成的氧化还原中性序列与肟氮形成推定的乙烯基铑中间体,其中肟衍生物的 NO 键可以作为内部氧化剂来维持催化循环。
Zinc-catalyzed reaction of isoxazoles with thioynol ethers involving an unprecedented 1,2-sulfur migration
作者:Xin-Qi Zhu、Qing Sun、Zhi-Xin Zhang、Bo Zhou、Pei-Xi Xie、Wen-Bo Shen、Xin Lu、Jin-Mei Zhou、Long-Wu Ye
DOI:10.1039/c8cc03140a
日期:——
A novel zinc-catalyzed reaction of isoxazoles with thioynol ethers involving an unprecedented 1,2-sulfur migration has been developed, which represents the first example of a non-noble metal-catalyzed reaction between isoxazoles and alkynes. This method allows the facile and atom-economical synthesis of a range of valuable β-keto enamides. Moreover, the computational study provides further evidence
Atropisomerism in 3,4,5-Tri-(2-methoxyphenyl)-2,6-lutidine
作者:Piotr Roszkowski、Dariusz Błachut、Jan K. Maurin、Magdalena Woźnica、Jadwiga Frelek、Franciszek Pluciński、Zbigniew Czarnocki
DOI:10.1002/ejoc.201301378
日期:2013.12
Suzuki reaction of tribromo-2,6-lutidine with (2-methoxyphenyl)boronic acid gave 3,4,5-tris(2-methoxyphenyl)-2,6-lutidine in the form of a mixture of three atropisomers that were stable at room temperature. Each isomer was isolated and fully characterized, including by X-ray structure determination. One of the isomers, being a racemic mixture, was separated into individual enantiomers by using semipreparative
三溴-2,6-二甲基吡啶与(2-甲氧基苯基)硼酸的铃木反应得到三种阻转异构体混合物形式的3,4,5-三(2-甲氧基苯基)-2,6-二甲基吡啶,在室内温度。每种异构体都经过分离和充分表征,包括通过 X 射线结构测定。其中一种异构体是外消旋混合物,通过使用半制备手性 HPLC 将其分离为单独的对映异构体。它们的绝对立体化学最初是根据 CD 光谱的计算计算确定的,最终通过 X 射线分析确认。
Balaban; Nenitzescu, Justus Liebigs Annalen der Chemie, 1959, vol. 625, p. 74,83