40596-20-1Relevant academic research and scientific papers
Palladium-Catalyzed Intermolecular Heck-Type Reaction of Epoxides
Teng, Shenghan,Tessensohn, Malcolm E.,Webster, Richard D.,Zhou, Jianrong Steve
, p. 7439 - 7444 (2018)
The palladium-catalyzed intermolecular Heck-type reaction of both cyclic and acyclic epoxides is reported with tolerance of typical polar groups and acidic protons. Suitable alkenes include styrenes, conjugate dienes, and some electron-deficient olefins. In reactions of aliphatic terminal epoxides, ring opening occurs selectively at terminal positions, and stereocenters of epoxides are fully retained. Mechanistic studies provide evidence for in situ conversion of epoxides to β-halohydrins, generation of alkyl radicals, and radical addition to alkenes as key steps. Cyclovoltammetric determination of reduction potentials suggests that during activation of alkyl iodides by palladium(0) complexes, inner-sphere halogen abstraction is more likely than outer-sphere single electron transfer.
Efficient hydroarylation of terminal alkynes with sodium tetraphenylborate performed in water under mild conditions
Koci?cka,Trzeciak
, (2019/11/02)
The hydroarylation of terminal alkynes with sodium tetraphenylborate was performed in high yield within 3 h at room temperature in water, using palladium(II) complexes with imidazole ligands as catalysts. Under these conditions, differently substituted phenylacetylene substrates were converted to arylalkenes and aryl-substituted dienes. High conversion and excellent selectivity were achieved in the hydroarylation of alkynols with sodium tetraphenylborate. Only one product, arylalkene with an OH group, was formed in these reactions with the yield dependent on the kind of alkynol used. A plausible hydroarylation reaction mechanism was proposed on the basis of the palladium species identified in the reaction mixture and H/D exchange studies. The contribution of water as the hydride source was evidenced.
