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• 930-22-3 epoxybutene 
• 536-74-3 phenylacetylene 

Relevant academic research and scientific papers

Ligand coordination- and dissociation-induced divergent allylic alkylations using alkynes

Efficient allylic alkylation of vinyl epoxides/aziridines with terminal alkynes can be achieved in the presence of nickel and copper catalysts. Intriguing ligand-induced divergent reactions are observed to produce either 1,4-enynes from bimolecular allylic alkynylation or dienynes from trimolecular alkyne dimerization/allylic alkylation. The allylic alkynylation reaction works well for a wide range of alkynes bearing a myriad of functionalities. An enantioconvergent transformation of racemic vinyl carbonates to enantioenriched 1,4-enynes is also realized.In transition metal catalysis, the nature of ligand coordination plays a vital role in defining the reactivity of the catalytic system. Achieving multi-substrate coordination and coupling by leveraging dynamic ligand dissociation is rare. Here, we report the discovery of such a phenomenon in nickel/copper-co-catalyzed divergent allylic alkylation of vinyl epoxides and aziridines using alkynes. Under otherwise identical conditions, the use of either strong bisphosphine ligands or hemilabile P,N-ligands leads to bimolecular allylic alkynylation or trimolecular dienyne formation, respectively. DFT calculations provide key insights for these ligand-induced divergent reactivities, particularly ligand-dissociation-enabled coordination of three substrates on nickel for trimolecular coupling. This catalytic system couples a remarkably broad range of readily available terminal alkynes with vinyl epoxides, carbonates, and aziridines in high regio- and stereo-selectivity. The utility of the versatile enyne and dienyne products, coupled with the use of abundant nickel/copper catalysts, makes this a practical method in synthetic and medicinal chemistry.Catalysis is a central concept in chemistry as it enables reactivity not attainable under reasonable conditions by other means and allows for more sustainable and economical processes. In transition metal catalysis, the nature of ligand coordination plays a vital role in the reactivity of the catalytic system. Ligand dissociation from the metal center is typically deemed a destructive scenario, and its alteration to achieve well-controlled reactivity is difficult to accomplish. We report here an intriguing example of leveraging dynamic ligand dissociation on nickel for divergent bimolecular or trimolecular allylic alkylation using terminal alkynes. This catalytic system shows a remarkable scope with superb functional group tolerance and may find wide use in the functionalization of alkyne-containing molecules. This discovery and the detailed mechanistic understanding obtained from DFT calculations will also direct future endeavors in the development of novel, divergent metal-catalyzed reactions.

The Ring Opening of Unsymmetrical Allylic, Benzylic, Propargylic, and Si-Substituted Epoxides by Titanium Acetylides: A Convenient Access to Certain 2-Substituted 3-Butyn-1-ols

Epoxides bearing aryl, alkenyl, alkynyl, and trimethylsilyl substituents react with titanium acetylides at the higher substituted carbon atom exclusively; the 2-substituted 3-butyn-1-ols thus formed are isolated in 33-79percent yield.The dependence of the yield on the solvent, the ratio of the reactands, and their structure is discussed and a reaction mechanism is proposed.