62808-75-7Relevant academic research and scientific papers
Fine-tuning dirhodium compounds with bridging ligands: Synthesis, structure, catalytic efficiency
Ning, Yangbo,Tan, Jiantao,Wang, Yuanhua,Wang, Zhifan
supporting information, (2021/09/28)
The structure of dirhodium compounds contains a unique Rh-Rh bond, two axial ligands and four bridging ligands. In the dirhodium(II) compounds, it is easy to migrate the coordinating atoms of the bridging ligand during the catalysis process, which leads to the degradation of the catalyst. Coordination atom migration was identified in bridging ligands. To improve the catalyst stability, we carried out a study on the effect of fine-tuning of the bridging ligand on the dirhodium compound. Several dirhodium compounds were designed and synthesized. During this process, we have successfully found Rh2(5-Br-esp)2 and Rh2(5-tBu-esp)2, which are closer to the ideal geometric configuration of the dirhodium(II) compounds. Rh2(5-Br-esp)2 has been applied in the oxidation of propargyl position and Rh2(5-tBu-esp)2 in the formation reaction of the C–N bond.
New approach for the general synthesis of oxotetrahydroindoles via intramolecular cycloadditions of azomethine ylides with tethered alkynes
Nayyar, Naresh K.,Hutchison, Darrell R.,Martinelli, Michael J.
, p. 982 - 991 (2007/10/03)
A new method for the synthesis of oxotetrahydroindoles has been achieved employing an intramolecular dipolar cycloaddition approach involving mesoionic species (munchnones) with electron-deficient alkynes. The methodology is quite general and convergent as shown by the synthesis of a variety of tri- and tetrasubstituted oxotetrahydroindoles 18, 21, 24, 27, 30, and 34. LiI-based ester cleavage in the presence of an electrophilic acetylenic ketone was critical for formation of the requisite cycloaddition substrates. The cycloaddition is virtually unaffected by the presence of gem-dimethyl groups in the side chain (cf. 38). The presence of a substituted benzyl or a phenethyl moiety on nitrogen, a polarized acetylene, and an appropriate tether between dipole and dipolarophile are essential for obtaining optimal efficiency.
An Efficient Synthesis of Acetylenic γ- and δ-Hydroxy Ketones, γ- and δ-Keto Acids, and γ-Diketones via Addition of 1-Alkinyllithium Compounds to γ- and δ-Lactones
Wedler, Christine,Schick, Hans
, p. 410 - 414 (2007/10/02)
2-Hydroxy-6-alkyn-5-ones 3, 1-hydroxy-5-alkyn-4-ones 4, and 1-hydroxy-6-alkyn-5-ones 5 are conveniently obtained in exellent yields through a highly selective monoaddition of an 1-alkynyllithium compound 2 to γ-valerolactone (1a), γ-butyrolactone (1b) or
