Organocatalytic Cyclization of COS and Propargylic Derivatives to Value‐Added Heterocyclic Compounds
作者:Hui Zhou、Rui Zhang、Sen Mu、Hui Zhang、Xiao‐Bing Lu
DOI:10.1002/cctc.201900490
日期:2019.12.5
and 1,3‐thiazolidine‐2,4‐diones derivatives in a highly chemo‐ and stereoselective manner. The isotope labeling and stoichiometric experiments suggested the LB‐COS adducts preferentially mediated basic ionic pair mechanism. Furthermore, the practical application of this methodology was highlighted by the highlyefficientsynthesis of rosiglitazone using COS as sulfur source.
A Gold‐Catalyzed Acid‐Assisted Regioselective Cyclization for the Synthesis of Polysubstituted Oxazoles
作者:Qian Wang、Stephanie Hoffmann、Jasmin Schießl、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/ejoc.201900699
日期:2020.5.3
derivatives are obtained through a regioselective gold‐catalyzed reaction of α‐alkynylamides and alkynoates in the presence of nitriles. The intermediary obtained gold carbenes are generated by an alkyne oxidation with a pyridine N‐oxide. Acidic conditions ensure that only one of the two carbonyl oxygen atoms in these intermediates selectively cyclizes to the products in excellent yields.
Palladium/Copper Bimetallic System-Mediated Cross-Coupling of Alkynes and Alkenes: Two Strategies to Suppress β-H Elimination on Alkyl-Palladium Center
efficient strategies to suppress β‐H elimination during the palladium/copper bimetallic system‐mediated cross‐coupling between alkynamides and alkenes. Remote donor groups with the terminal olefins, such as toluenesulfonamide, phosphate, sulfone, etc., cooperate with the amide of alkynamides and chelate the palladium active center, to promote C(sp3)O bond formation by suppressing the β‐H elimination
Carbondioxide is a harmful greenhouse gas, as well as a valuable resource. Here, a three-component cyclization reaction was developed for the synthesis of oxazolidine-2,4-diones by immobilizing CO2 under the electrochemistry and copper catalyst. Propargyl amide was used as the reaction substrate to capture carbondioxide to produce carboxyl anion, while selenide produced electrophilic receptor to