Iridium-Catalyzed Borylation of Secondary C–H Bonds in Cyclic Ethers
摘要:
The borylation of secondary C-H bonds, specifically secondary C-H bonds of cyclic ethers, with a catalyst generated from tetramethylphenanthroline and an iridium precursor is reported. This borylation occurs with unique selectivity for the C-H bonds located beta to the oxygen atoms over the weaker C-H bonds located alpha to oxygen atoms. Mechanistic studies imply that the C-H bond cleavage occurs directly at the beta position rather than at the alpha position followed by isomerization of a reaction intermediate.
A novel electromagnetic mill promoted mechanochemical solid-state Suzuki–Miyaura cross-coupling reaction using ultra-low catalyst loading
作者:Xin Li、Yunxia Liu、Lizhi Zhang、Yunhui Dong、Qing Liu、Daopeng Zhang、Lei Chen、Zengdian Zhao、Hui Liu
DOI:10.1039/d2gc01427k
日期:——
The Nobel-prize-winning Suzuki–Miyauracross-coupling (SMC) is a practical and attractive strategy for the construction of C–C bonds in both academic and industrial settings. However, the development of solid-state SMC reactions remains extremely scarce. Herein, we report an electromagnetic mill (EMM) promoted solid-state SMC reactionusing ultra-low palladium loading (0.05 mol%) without any liquid
A General C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Cross-Coupling of Benzyl Sulfonylhydrazones with Alkyl Boronic Acids
作者:Rohan R. Merchant、Jovan A. Lopez
DOI:10.1021/acs.orglett.0c00471
日期:2020.3.20
A general transition-metal-free cross-coupling between benzylic sulfonylhydrazones and 1 degrees, 2 degrees, or 3 degrees alkyl boronic acids is reported. The base-promoted reaction is operationally simple and exhibits a broad substrate scope to forge a variety of alkyl-alkyl bonds, including between sterically encumbered secondary and tertiary sp(3)-carbons. The ability of this method to simplify retrosynthetic analysis is exemplified by the improved synthesis of multiple medicinally relevant scaffolds.
Iridium-Catalyzed Borylation of Secondary C–H Bonds in Cyclic Ethers
作者:Carl W. Liskey、John F. Hartwig
DOI:10.1021/ja305596v
日期:2012.8.1
The borylation of secondary C-H bonds, specifically secondary C-H bonds of cyclic ethers, with a catalyst generated from tetramethylphenanthroline and an iridium precursor is reported. This borylation occurs with unique selectivity for the C-H bonds located beta to the oxygen atoms over the weaker C-H bonds located alpha to oxygen atoms. Mechanistic studies imply that the C-H bond cleavage occurs directly at the beta position rather than at the alpha position followed by isomerization of a reaction intermediate.
Synergistic Photoredox/Nickel Coupling of Acyl Chlorides with Secondary Alkyltrifluoroborates: Dialkyl Ketone Synthesis
作者:Javad Amani、Gary A. Molander
DOI:10.1021/acs.joc.6b02897
日期:2017.2.3
Visiblelightphotoredox/nickel dual catalysis has been employed in the cross-coupling of acyl chlorides with potassium alkyltrifluoroborates. This protocol, based on single-electron-mediated alkyl transfer, circumvents the restriction of using reactive alkylmetallic nucleophiles in transition-metal-catalyzed acylation and achieves a mild and efficient method for the synthesis of unsymmetrical alkyl