Heteropolyacid-Catalyzed Direct Deoxygenation of Propargyl and Allyl Alcohols
摘要:
The combination of H-3[PW12O40]center dot nH(2)O (1 mol %) and Et3SiH led to the direct catalytic deoxygenation of propargyl alcohols, in which proper solvent selection Cl(CH2)(2)Cl vs CF3CH2OH was the key to obtaining better product yields. Under similar conditions, the deoxygenation of allyl alcohols proceeded to give thermodynamically stable alkenes with migration of the double bonds in good yields.
Propargylsilanes as Reagents for Synergistic Gold(I)‐Catalyzed Propargylation of Carbonyl Compounds: Isolation and Characterization of σ‐Gold(I) Allenyl Intermediates
Reported herein is the isolation and characterization, for the first time, of a σ‐gold allenyl complex as an intermediate in gold catalysis. This intermediate was captured during the study of a novel gold(I)‐catalyzed propargylation of carbonyl compounds with propargylsilanes. Notably, the gold‐catalyzed propargylation reaction, which proceeds with aldehydes and ketones, can be driven to the formation
Construction of All-Carbon Quaternary Centers through Cu-Catalyzed Sequential Carbene Migratory Insertion and Nucleophilic Substitution/Michael Addition
作者:Chengpeng Wang、Fei Ye、Chenggui Wu、Yan Zhang、Jianbo Wang
DOI:10.1021/acs.joc.5b01592
日期:2015.9.4
cross-coupling reaction of terminal alkyne, α-diazo ester, and alkyl halide has been developed. This transformation involves sequent migratory insertion of copper-carbene and nucleophilic substitution, in which a C(sp)–C(sp3) bond and a C(sp3)–C(sp3) bond are formed successively on a carbenic center. Michael addition acceptors can also be employed instead of alkyl halides that enable Michael addition to
Pd-catalyzed sp–sp<sup>3</sup> cross-coupling of benzyl bromides using lithium acetylides
作者:Anirban Mondal、Paco Visser、Anna M. Doze、Jeffrey Buter、Ben L. Feringa
DOI:10.1039/d1cc02762j
日期:——
Organolithium-based cross-couplingreactions have emerged as an indispensable method to construct C–C bonds. These transformations have proven particularly useful for the direct and fast coupling of various organolithium reagents (sp, sp2, and sp3) with aromatic (pseudo) halides (sp2). Here we present an efficient method for the cross-coupling of benzyl bromides (sp3) with lithium acetylides (sp). The reaction proceeds
Bifunctional Biphenyl-2-ylphosphine Ligand Enables Tandem Gold-Catalyzed Propargylation of Aldehyde and Unexpected Cycloisomerization
作者:Ting Li、Liming Zhang
DOI:10.1021/jacs.8b12478
日期:2018.12.19
been invoked as catalytic intermediates and their reactivities not studied. This work reports for the first time they are generated in situ and undergo nucleophilic addition to activated aldehydes in a bifunctional phosphine ligand-enabled gold catalysis. This development reveals a broad range of opportunities to achieve propargylic C-H functionalization for the first time under catalytic and mild conditions
highly efficient palladium-catalyzed Sonogashira coupling of benzylic ammonium salts with terminal alkynes is developed. This strategy provides a facile access to a series of internal alkyne derivatives in moderate to excellent yields via C-N bond cleavage and C(sp3)-C(sp) bondformation. The broad substrate scope and high functionalgroup tolerance make this reaction attractive for organic synthesis