Related Experiment Video
Updated: Sep 10, 2025

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes
Published on: September 8, 2013
Synthesis and Reactivity of Terminal U(IV) Hydrides Including the Isolation of a κ1-Formate
M Gayanethra Kaumini1, Iker Del Rosal2, Pokpong Rungthanaphatsophon1
1Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
None:
Formation of a rare terminal U(IV) hydride complex, [(C5Me5)2(2,6-tBu2-4-MeC6H2O)U(H)], was accomplished through the hydrogenation of a uranium(IV) metallocene hydrocarbyl complex. The reactivity of this hydride was probed with a variety of substrates to examine sigma-bond metathesis, PhEEPh (E = S, Se, Te), and insertion (CO2, CH2═CH2) reactivity. While the reaction of CO did not produce an isolable result, using the U(IV) hydride with a less sterically encumbering mesityl aryloxide, an ethenediolate is formed, [{(C5Me5)2(MesO)U}2(μ2-OC(H)═C(H)O], Mes = mesityl, 2,4,6-Me3C6H2. Each complex has been characterized by NMR, IR, and X-ray crystallographic analysis.
More Related Videos
10:51The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
09:54Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
Related Concept Videos
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Reactions of Acid Anhydrides
Radical Reactivity: Intramolecular vs Intermolecular