镍催化的交叉亲电偶联最近已成为形成 CC 键的高效实用方法。通过将此过程与成熟的 π-π 偶联化学相结合,开发了一种合成四取代烯烃的新方法。该过程依赖于使用氯硅烷作为产生反应性乙烯基镍中间体的手段,这些中间体能够与卤代烷进行还原性交叉亲电偶联。该方法不仅可以生成高度取代的烯丙醇衍生物,而且不需要化学计量的有机金属亲核试剂,与以前开发的方法相比,范围和官能团耐受性大大提高。
SeO<sub>2</sub>-Mediated Oxidative Transposition of Pauson–Khand Products
作者:Sara E. Dibrell、Michael R. Maser、Sarah E. Reisman
DOI:10.1021/jacs.9b13818
日期:2020.4.8
Oxidative transpositions of bicyclic cyclopentenones mediated by selenium dioxide (SeO2) are disclosed. Treatment of Pauson-Khand reaction (PKR) products with SeO2 in the presence or absence of water furnishes di- and trioxidized cyclopentenones, respectively. Mechanistic investigations reveal multiple competing oxidation pathways that depend on substrate identity and water concentration. Functionalization
Rhodium(<scp>i</scp>)-catalyzed Pauson–Khand-type reaction using formic acid as a CO surrogate: an alternative approach for indirect CO<sub>2</sub> utilization
作者:Xian-Dong Lang、Fei You、Xing He、Yi-Chen Yu、Liang-Nian He
DOI:10.1039/c8gc03933j
日期:——
(PK-type) reaction of various substituted 1,6-enynes to afford bicyclic cyclopentenones in moderate to good yields. High TON value of up to 263 and good results in the gram-scale experiment were also obtained, demonstrating the efficacy of this methodology. In addition, heterocyclic molecules of pharmaceutical importance were also furnished via inter- or intra-molecular hetero-PK-type reactions, further
Formate as a CO surrogate for cascade processes: Rh-catalyzed cooperative decarbonylation and asymmetric Pauson–Khand-type cyclization reactions
作者:Hang Wai Lee、Albert S. C. Chan、Fuk Yee Kwong
DOI:10.1039/b702718d
日期:——
A rhodium-(S)-xyl-BINAP complex-catalyzed tandem formate decarbonylation and [2 + 2 + 1] carbonylative cyclization is described; this cooperative process utilizes formate as a condensed CO source, and the newly developed cascade protocol can be extended to its enantioselective version, providing up to 94% ee of the cyclopentenone adducts.
Remote ether groups-directed regioselective and chemoselective cycloaddition of azides and alkynes
作者:Xuelun Duan、Nan Zheng、Ming Li、Xinhao Sun、Zhuye Lin、Pan Qiu、Wangze Song
DOI:10.1016/j.cclet.2021.05.037
日期:2021.12
5-regioselectivities and excellent chemoselectivities. Ether group could coordinate with iridium catalyst by lone-pair electron at a distance (up to four σ bonds) away from alkyne to control the regioselectivity by weak coordination effect. The cycloaddition reaction chemoselectively occurred at the propargyl ether moiety of diyne to give unique fully substituted 4-alkynyl-triazole.
The reaction of enynes with aldehydes in the presence of a catalytic amount of [RhCl(cod)](2)/dppp results in the Pauson-Khand-typereaction without the use of gaseous carbon monoxide to give bicyclic cyclopentenones in high yields (14 examples). Aldehydes serve as a source of carbon monoxide, and their carbonyl moiety is transferred to enynes, resulting in the formation of the carbonylated products
在催化量的 [RhCl(cod)](2)/dppp 存在下,烯炔与醛的反应会导致 Pauson-Khand 型反应,而无需使用气态一氧化碳,以高产率得到双环环戊烯酮 (14例子)。醛作为一氧化碳的来源,它们的羰基部分被转移到烯炔,导致形成羰基化产物。该反应代表了 CO 转移羰基化的第一个例子。