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101.
A new approach to the enantiocontrolled synthesis of α-amino ketone derivatives is disclosed by employing a decarboxylative acylation strategy. Thus, when an acyl chloride and an α-amido-containing redox-active ester are exposed to a nickel catalyst, chiral ligand, and metal reductant, α-amido ketones are produced in good yield and high ee. The reaction exhibits broad substrate scope, can be easily scaled up, and is applied to dramatically simplify the synthesis of several known structures. 相似文献
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Dr. Sida Wang Dr. Phil Liebing Dr. Martin Feneberg Prof. Farid M. Sroor Dr. Felix Engelhardt Dr. Liane Hilfert Dr. Sabine Busse Elias Kluth Prof. Dr. Rüdiger Goldhahn Prof. Dr. Frank T. Edelmann 《欧洲无机化学杂志》2023,26(14):e202300027
A series of new alkynylamidinate complexes of selected first and second row transition metals has been synthesized and fully characterized. Treatment of MCl2 precursors (M=Mn, Fe, Co) with 2 equiv. of the lithium alkynylamidinates Li[c-C3H5−C≡C−C(NR′)2] ⋅ THF (R′=iPr (2), Cy (cyclohexyl) ( 2 )) afforded a series of binuclear complexes of the type M2[c-C3H5−C≡C−C(NR)2-κN:κN′]2[c-C3H5−C≡C−C(NR)2-κ2N,N′]2 ( 3 : M=Mn, R=Cy; 4 a : M=Fe, R=iPr; 4 b : M=Fe, R=Cy; 5 : M=Co, R=iPr) with no significant metal-metal bonding. In marked contrast, a similar reaction of CrCl2 with 2 equiv. of 1 afforded the homoleptic dinuclear chromium(II) complex Cr2[c-C3H5−C≡C−C(NiPr)2-κN:κN′]4 ( 6 ) which supposedly comprises a Cr−Cr quadruple bond. Complex 6 could also be prepared in a more rational way and in better yield (61 %) by using dichromium(II) tetraacetate, Cr2(OAc)4, as starting material. Related reactions employing dimolybdenum(II) tetraacetate, Mo2(OAc)4, and 2 or 3 equiv. of 1 afforded the mixed-ligand paddle wheel-type complexes trans-Mo2(OAc-κO:κO′)2([c-C3H5−C≡C−C(NiPr)2-κN:κN′]2 ( 7 ) and Mo2(OAc-κO:κO′)([c-C3H5−C≡C−C(NiPr)2-κN:κN′]3 ( 8 ). All title compounds were structurally characterized through single-crystal X-ray diffraction and spectroscopic techniques (NMR, IR, Raman). 相似文献
103.
Synthesis and Structural Characterization of New Zirconium(IV) Bent Metallocenes comprising η8‐Cyclooctatetraenyl and Bulky Cyclopentadienyl Ligands 下载免费PDF全文
Janek Rausch Phil Liebing Marcel Kühling Volker Lorenz Cristian G. Hrib Liane Hilfert Frank T. Edelmann 《无机化学与普通化学杂志》2017,643(16):1063-1066
The new zirconium bent metallocenes (COT)Zr(CptBu2)Cl ( 1 ) and (COT)Zr(Cp′′)Cl ( 2 ) were synthesized in a straightforward manner and in high yields ( 1 : 91 %, 2 : 86 %) by treatment of in situ‐prepared (COT)ZrCl2(THF) with 1 equiv. of K(CptBu2) or K(Cp′′), respectively (COT = η8‐cyclooctatetraenyl; CptBu2 = η5‐1,3‐di‐tert‐butylcyclopentadienyl; Cp′′ = η5‐1,3‐bis(trimethylsilyl)cyclopentadienyl). Subsequent reaction of 1 with 1 equiv. of phenyllithium afforded the σ‐phenyl derivative (CptBu2)Zr(COT)Ph ( 3 ) as orange crystals in 83 % isolated yield. All three new compounds were structurally characterized through single‐crystal X‐ray diffraction. 相似文献
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Sung Phil Mun 《Molecules (Basel, Switzerland)》2022,27(24)
Pinus radiata bark is a rich source of polyphenols, which are mainly composed of proanthocyanidins. This study aimed to utilize P. radiata bark as a polyol source for bio-foam production in the future. Polyphenol-rich alkaline extracts (AEs) from P. radiata bark were prepared by mild alkaline treatment and then derivatized with propylene oxide (PO). Hydroxypropylated alkaline extracts (HAEs) with varying molar substitutions (MS 0.4–8.0) were characterized by FT-IR, NMR, GPC, TGA, and DSC. The hydroxyl value and solubility in commercial polyols were also determined. The molecular weights of the acetylated HAEs (Ac-HAEs) were found to be 4000 to 4900 Da. Analyses of FT-IR of HAEs and 1H NMR of Ac-HAEs indicated that the aromatic hydroxyl groups were hydroxypropylated and showed an increase in aliphatic hydroxyl group content. The glass transition temperature (Tg) of AE and HAEs were 58 to 60 °C, showing little difference. The hydroxyl value increased as the hydroxypropylation proceeded. Although salts were produced upon neutralization after hydroxypropylation, HAEs still showed suitable solubility in polyether and polyester polyols; HAEs dissolved well in polyether polyol, PEG#400, and solubility reached about 50% (w/w). This indicated that neutralized HAEs could be directly applied to bio-foam production even without removing salts. 相似文献