7443-70-1Relevant articles and documents
Reaction of Potassium Triphenylborohydride with Selected Organic Compounds Containing Representative Functional Groups
Yoon, Nung Min,Kim, Kwan Eung
, p. 5564 - 5570 (1987)
Potassium triphenylborohydride (KTPBH) is a very mild reducing agent.With the exception of aldehyde, ketone, quinone, phenyl isocyanate, n-alkyl iodide, and aromatic disulfide, most functional groups studied react slowly or are inert toward KTPBH.KTPBH exhibits a remarkable stereoselectivity in the reduction of cyclic ketones.The reductions of epoxides are very slow, but the presence of the Lewis acid Ph3B dramatically accelerates the rates and chenges the regioselectivity in the case of trisubstituted epoxides.
Demystifying Cp2Ti(H)Cl and Its Enigmatic Role in the Reactions of Epoxides with Cp2TiCl
Gordon, Jonathan,Hildebrandt, Sven,Dewese, Kendra R.,Klare, Sven,Gans?uer, Andreas,Rajanbabu,Nugent, William A.
supporting information, p. 4801 - 4809 (2019/01/08)
The role of Cp2Ti(H)Cl in the reactions of Cp2TiCl with trisubstituted epoxides has been investigated in a combined experimental and computational study. Although Cp2Ti(H)Cl has generally been regarded as a robust species, its decomposition to Cp2TiCl and molecular hydrogen was found to be exothermic (ΔG = -11 kcal/mol when the effects of THF solvation are considered). In laboratory studies, Cp2Ti(H)Cl was generated using the reaction of 1,2-epoxy-1-methylcyclohexane with Cp2TiCl as a model. Rapid evolution of hydrogen gas was demonstrated, indicating that Cp2Ti(H)Cl is indeed a thermally unstable molecule, which undergoes intermolecular reductive elimination of hydrogen under the reaction conditions. The stoichiometry of the reaction (Cp2TiCl:epoxide = 1:1) and the quantity of hydrogen produced (1 mol per 2 mol of epoxide) is consistent with this assertion. The diminished yield of allylic alcohol from these reactions under the conditions of protic versus aprotic catalysis can be understood in terms of the predominant titanium(III) present in solution. Under the conditions of protic catalysis, Cp2TiCl complexes with collidine hydrochloride and the titanium(III) center is less available for "cross-disproportionation" with carbon-centered radicals; this leads to byproducts from radical capture by hydrogen atom transfer, resulting in a saturated alcohol.
Mild and Regioselective Hydroxylation of Methyl Group in Neocuproine: Approach to an N,O-Ligated Cu6 Cage Phenylsilsesquioxane
Bilyachenko, Alexey N.,Levitsky, Mikhail M.,Khrustalev, Victor N.,Zubavichus, Yan V.,Shul'Pina, Lidia S.,Shubina, Elena S.,Shul'Pin, Georgiy B.
supporting information, p. 168 - 171 (2018/02/06)
The self-Assembly synthesis of Cu(II)-silsesquioxane involving 2,9-dimethyl-1,10-phenanthroline (neocuproine) as an additional N ligand at copper atoms was performed. The reaction revealed an unprecedented aerobic hydroxylation of only one of the two methyl groups in neocuproine to afford the corresponding geminal diol. The produced derivative of oxidized neocuproine acts as a two-centered N,O ligand in the assembly of the hexacopper cage product [Cu6(Ph5Si5O10)2·(C14H11N2O2)2] (1), coordinating two of the six copper centers in the product. Two siloxanolate ligands [PhSi(O)O]5 in the cis configuration coordinate to the rest of the copper(II) ions. Compound 1 is a highly efficient homogeneous precatalyst in the oxidation of alkanes and alcohols with peroxides.
