Substrate-Controlled Cu(OAc)₂-Catalyzed Stereoselective Semi-Reduction of Alkynes with MeOH as the Hydrogen Source

Abstract

A substrate-controlled stereoselective semi-reduction of alkynes with MeOH as the hydrogen source has been developed, and readily available Cu(OAc) 2 (copper acetate) is utilized as an optimal catalyst. The detailed investigation of the mechanism revealed distinct catalytic processes for the ( Z )- and ( E )-alkenes, respectively. As a result, a diversity of alkynes (including terminal, internal alkynes etc.) were compatible under the mild reaction conditions. Furthermore, the high proportion of deuterium in Z -alkenes (up to 96%) was obtained using d 4 -methanol as a solvent.

Thermodynamics of the elementary steps of organic hydride chemistry determined in acetonitrile and their applications

“…Alkynes, which are another type of important unsaturated compound, are usually applied to be selectively reduced to give alkenes. 109,110 Many excellent works focused on the effective reduction of alkynes. 109,110 However, we wanted to investigate the differences in the thermodynamic driving forces of alkynes and alkenes in hydrogenation reactions for a long time.…”

“…109,110 Many excellent works focused on the effective reduction of alkynes. 109,110 However, we wanted to investigate the differences in the thermodynamic driving forces of alkynes and alkenes in hydrogenation reactions for a long time. Luckily, we chose 4-substituted-1-phenyl-2-benzensulfonyl ethynes (E) and the corresponding 4-substituted-1-phenyl-2-benzensulfonyl ethenes (EH 2 ) to determine and compare each elementary step on E and EH 2 being hydrogenated to alkenes and alkanes using our established experimental method in previous papers.…”

Stereoselective Semi‐Hydrogenations of Alkynes by First‐Row (3d) Transition Metal Catalysts

“…Similarly, an alternative B 2 pin 2mediated approach was presented in a recent report by Huang and co-workers. [115] The Cu catalyst is formed in situ by the action of 4,4'-bipyridine on Cu(OAc) 2 2H 2 O. Contrary to Bao et al, [114] only a sub-stoichiometric amount of KO t Bu (0.3 equiv.)…”

Methanol as a Potential Hydrogen Source for Reduction Reactions Enabled by a Commercial Pt/C Catalyst

“…Methylcyclohexane (42). 72 It is obtained as a colorless liquid (44.21 mg, 90%) after purification by column chromatography (n-hexane/ EtOAc: 90:10).…”