Ene Hydroperoxidation of Isobutenylarenes within Dye-Exchanged Zeolite Na−Y: Control of Site Selectivity by Cation−Arene Interactions
作者:Manolis Stratakis、Constantinos Rabalakos、Giannis Mpourmpakis、George E. Froudakis
DOI:10.1021/jo020599g
日期:2003.4.1
The site selectivity in the singlet oxygen ene reaction of several deuterium-labeled isobutenylarenes depends on the position and the electronic nature of the aryl substitutents. For example, 1-(4-trifluoromethylphenyl)-2-methylpropene gives 82% twin selectivity whereas the isomeric 1-(2-trifluoromethylphenyl)-2-methylpropene gives 68% twix selectivity. If photooxygenation of these CF3-substituted compounds is carried out in solution, the opposite selectivity trends are found. On the basis of DFT calculations, these results are rationalized in terms of oxygen-cation and cation-arene interactions.
Intercepting Wacker Intermediates with Arenes: C–H Functionalization and Dearomatization
作者:Bryan S. Matsuura、Allison G. Condie、Ryan C. Buff、Gregory J. Karahalis、Corey R. J. Stephenson
DOI:10.1021/ol202881q
日期:2011.12.2
An intramolecular cyclization cascade reaction has been developed utilizing a high valent palladium intermediate that generates a carbon–carbon and carbon–oxygen bond in a single transformation. This method provides rapid access to highly functionalized tricyclic scaffolds, including spirocyclic cyclohexadienones. Good yields and mild conditions are reported with high tolerance toward oxygen and water
We developed a copper-catalyzed enantio- and diastereoselective boron conjugate addition to α-alkyl α,β-unsaturated esters under base-free conditions. The approach showed excellent enantioselectivities (87–99% ee) and moderate to good conversions (51–99%), albeit with moderate diastereoselectivities (1 : 1–17 : 1 dr). The synthetic utility of this protocol was demonstrated.