Copper(I)-Catalyzed Oxidation of Alkenes Using Molecular Oxygen and Hydroxylamines: Synthesis and Reactivity of α-Oxygenated Ketones
作者:Alexander A. Andia、Matthew R. Miner、K. A. Woerpel
DOI:10.1021/acs.orglett.5b01120
日期:2015.6.5
The copper(I)-catalyzed oxidation of alkenes with molecularoxygen and N-hydroxyphthalimide (NHPI) or N-hydroxybenzotriazole (HOBt) provided α-oxygenated ketones. The reaction proceeded under a balloon of O2 at room temperature to furnish the dioxygenated products in 50–90% yield. These compounds, particularly the HOBt derivatives, can be further functionalized with phosphorus, nitrogen, and sulfur
Seven-membered metallacyclic allene compounds, 1-zirconacyclohepta-2,3,6-trienes, were synthesized by intermolecular coupling between alkynes and 1-en-3-ynes on a zirconium atom. X-ray diffraction studies and NMR spectroscopic observation indicated their seven-membered structures, although the contribution from 2-alkynyl-1-zirconacyclopent-4-ene might be considered. Benzyne, an unstable alkyne, also
Reactions of Carbon Electrophiles with Cobalt-Coordinated Enynes: Scope and Limitations
作者:Herbert Mayr、Oliver Kuhn、Clemens Schlierf、Armin R Ofial
DOI:10.1016/s0040-4020(00)00347-1
日期:2000.6
increases the nucleophilic reactivity of enynes by a factor of > 106. The exchange of one CO ligand by PPh3 (2a→2d), however, has only little effect on the reactivity of the enyne moiety. The second-order rate constants match the linearfreeenergyrelationship lg k20°C=s(E+N) and allow to determine the nucleophilicity parameters N and s for 2a–d. It is shown that at −70°C, electrophiles with E>0 are able to
Regioselective solvent-dependent benzannulation of conjugated enynes
作者:Florian Pünner、Gerhard Hilt
DOI:10.1039/c2cc30777d
日期:——
transformation of enynes under cobalt-catalysis leads to symmetrical benzannulation products in dichloromethane. In tetrahydrofuran the cobalt-catalysed reactions afforded the unprecedented unsymmetrical benzannulation products in moderate to good yields and good regioselectivities. In addition, cyclotrimerisation of the alkyne subunit can be realised when electron-deficient enynes are applied in the
Cu<sup>I</sup>-Catalyzed Synthesis of Propargyl Hydroperoxides Using Molecular Oxygen and Hydroxylamines
作者:Matthew R. Miner、K. A. Woerpel
DOI:10.1002/ejoc.201600038
日期:2016.4
A CuI-catalyzed oxidation of enynes using N-hydroxybenzotriazole (HOBt) or N-hydroxyphthalimide (NHPI) with molecular oxygen has been developed to yield propargylhydroperoxides. The reaction occurs under O2 at 0 °C to afford hydroperoxides in 1–4 h. This method provides an alternative to H2O2 or tBuOOH by using molecular oxygen as the source of oxygen atoms. The resulting hydroperoxides can be protected