205,832 research outputs found
Gold-Catalyzed C(sp3)-C(sp2) Suzuki-Miyaura Coupling Reaction
No full textA gold-catalyzed C(sp3)-C(sp2) Suzuki-Miyaura coupling reaction facilitated by the ligand-enabled Au(I)/Au(III) redox catalysis was developed. The cross-coupling of alkyl organometallics was first realized in the redox catalytic cycle in gold chemistry, without the use of external oxidants. This gold-catalyzed C(sp3)-C(sp2) coupling reaction allows a varie-ty of chain alkyl and useful methyl trifluoroborates to react with aryl and vinyl iodides under very mild conditions, which provides a complementary reactivity pattern for the challenging coupling with alkyl organometallics. The strong synthesis ability of this gold-catalyzed Suzuki-Miyaura coupling reaction is also demonstrated by its good functional-group compatibility and late-stage application of complicated biomolecules
Iron-Catalyzed C(sp2)-C(sp3) Suzuki Cross-Coupling Using an Alkoxide Base
No full textThe synthesis and characterization of iron(II) alkyl precatalysts for C(sp2)–C(sp3) Suzuki-Miyaura cross-coupling of aryl boronic esters and alkyl bromides is described. Addition of phenoxyimines (FI) to (py)2Fe(CH2SiMe3)2 (py = pyridine) afforded the high-spin iron(II) alkyl derivatives, (FI)Fe(CH2SiMe3)(py) with varying N-imine substituents. With both neopentyl glycol-protected (BNeo) and pinacol-protected boronic ester (BPin) aryl nucleophiles, an iron-catalyzed cross-coupling method was realized that utilized synthetically preferred alkoxide bases. Optimal performance was observed in non-polar solvents with anisole and fluorobenzene identified as more benign alternatives to benzene. The scope of this transformation included high efficiency C(sp2)–C(sp3) bond formation with both primary and secondary alkyl bromides with electron-deficient aryl and heteroaryl nucleophiles. Radical clock experiments support the formation of electrophile-derived radicals during catalysis and experiments with pre-formed potassium aryl boronates demonstrate the role of boronate intermediates in transmetalation
Suzuki-Miyaura diversification of amino acids and dipeptides in aqueous media
No full textThe authors gratefully acknowledge the IWT Flanders and Janssen Pharmaceutica for financial support of T.W. This work is supported by the Scientific Research Network (WOG) “Sustainable chemistry for the synthesis of fine chemicals” of the Research Foundation - Flanders (FWO).The Suzuki-Miyaura derivatisation of free amino acids, peptides and proteins is an attractive area with much potential utility for medicinal chemistry and chemical biology. Here we report the modification of unprotected and Boc-protected aromatic amino acids and dipeptides in aqueous media, enabling heteroarylation and vinylation. We systematically investigate the impact of the peptide backbone and adjacent amino acid residues upon the reaction. Our studies reveal that whilst asparagine and histidine hinder the reaction, by utilising dppf, a ferrocene-based bidentate phosphine ligand, cross-coupling of halophenylalanine or halotryptophan adjacent to such a residue could be enabled. Our studies reveal dppf to have good compatibility with all unprotected, proteinogenic amino acid side chains.Peer reviewe
Synthesis of C-aryl-flavonold derivatives via Suzuki-Miyaura coupling reaction
No full textA variety of 4'- and 3-C-aryl-quercetin derivatives were conveniently synthesized via Suzuki-Myaura coupling of the corresponding quercetin-O-triflates with aryl boronic acids or boronates
Crossing boundaries: Suzuki Bokushi (1770-1842) and the rural elite of Tokugawa Japan
No full textThis thesis centres on a member of the rural elite, Suzuki Bokushi (1770-1842) of Echigo, and his social environment in Tokugawa Japan (1603-1868). Through a case study of the interaction between one individual’s life and his social conditions, the thesis participates in the ongoing scholarly reassessment of Tokugawa society, which had an apparently rigid political and social structure, yet many features that suggest a prototype of modernity. Bokushi’s life was multifaceted. He was a village administrator, landlord, pawnbroker, poet, painter, and great communicator, with a nation-wide correspondence network that crossed various social classes. His remote location and humble lifestyle notwithstanding, he was eventually able to publish a book about his region, Japan’s ‘snow country’. This thesis argues that Bokushi’s life epitomises both the potentiality and the restrictions of his historical moment for a well-placed member of the rural elite. An examination of Bokushi’s life and texts certainly challenges residual notions of the rigidity of social boundaries between the urban and the rural, between social statuses, and between cultural and intellectual communities. But Bokushi’s own actions and attitudes also show the force of conservative social values in provincial life. His activities were also still restrained by the external environment in terms of geographical remoteness, infrastructural limitation, political restrictions, cultural norms and the exigencies of human relationships. Bokushi’s life shows that in his day, Tokugawa social frameworks were being shaken and reshaped by people’s new attempts to cross conventional boundaries, within, however, a range of freedom that had both external and internal limits
DFT Study of Unstrained Ketone C-C Bond Activation via Rhodium(I)-Catalyzed Suzuki-Miyaura Cross-Coupling Reactions
No full textUnstrained cyclic ketones can participate in cooperative Suzuki-Miyaura cross-coupling type reaction using rhodium(I)-based catalyst via C-C bond activation. The regioselectivity indicates a trend where the most substituted side is activated and it is controlled by the beta-substituents. In this work, Density Functional Theory (DFT) calculations have been carried out to disclose the underlying mechanism in the reaction of a ketone series and arylboronate using ylidene as ancillary ligand and pyridine as co-catalysts. The computed energies suggest the reductive elimination step with the highest energy while the reductive elimination has the highest energy barrier. By the means of the Activation Strain Model (ASM) of chemical reactivity, it is found that the ketone strain energy released on the oxidative addition does not control the relativity of the OA reactivity, but indeed is the interaction energy between Rh(I) and C-C bond the ruling effect. The effect of the beta-substituents on regioselectivity has been additionally studied
Solid-Phase Suzuki Coupling for C−C Bond Formation
No full textSolid-Phase Suzuki Coupling for C−C Bond
Formatio
C-groups of Suzuki type
No full textWe prove that the only C-groups constructed from an almost simple group G of Suzuki type are of rank 3. Moreover, we show that in all cases, G must be simple and that there exist always a string C-group and a non-string C-group for Sz(q).SCOPUS: ar.jinfo:eu-repo/semantics/publishe
2-Jód-1-C-metoxikarbonil-szubsztituált galaktál származék szintézise és Suzuki-Miyaura kapcsolási reakcióban való alkalmazása
No full textA dolgozatomban az átmenetifémek által katalizált kapcsolási reakciókkal foglalkoztam, részletesebben kitérve a Suzuki-Miyaura reakcióra a glikálok köráben.Vegyészmérnök BscBSc/B
Suzuki-Miyaura C-C coupling reaction of arylhalide with phenylboronic acid.
No full text<p>Suzuki-Miyaura C-C coupling reaction of arylhalide with phenylboronic acid.</p
- …
