A mild and efficient one-pot visible light-induced method has been developed for the allylic oxidation. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones. The allylic C-H oxidation is relatively simple and predictable, even on a preparative scale, because active species generated at the allylic position are stabilized by the double bond.
Selective arylation at the vinylic site of cyclic olefins
作者:Xiaojin Wu、Jianrong (Steve) Zhou
DOI:10.1039/c3cc41722k
日期:——
Cyclicolefins usually give Heck products having an aryl ring residing at the allylic or homoallylic position. We describe herein a new method that allows arylation at the vinylic position of various cyclicolefins.
Ten 2‐aryl‐3‐(2′,4′‐dinitrophenylthio)cyclohexenes were prepared, their 1H NMR spectra measured and chemical shifts assigned on the basis of nuclear Overhauser enhancements, H,H‐COSY spectra and other considerations. Analysis of the data suggests the preference of the conformer with (i) the arylthio group in the axial orientation and (ii) the dinitrophenyl group oriented away from the cyclohexene ring
Achieving Vinylic Selectivity in Mizoroki-Heck Reaction of Cyclic Olefins
作者:Xiaojin Wu、Yunpeng Lu、Hajime Hirao、Jianrong Steve Zhou
DOI:10.1002/chem.201204427
日期:2013.5.3
In Heck reactions of cyclicolefins, the products usually have aryl groups that end up at the allylic and/or homoallylic position. We herein report new selectivity that adds aryl groups to the vinylic position. Cyclicolefins of various ring size worked well. The desired isomers were produced by palladium–hydride‐catalyzed isomerization of the initial products. Thus, a specific catalyst must be used
The Effect of Reduced Osmium Amounts on the Asymmetric Dihydroxylation of 1-Arylcyclohexenes
作者:John McIntosh、E. Kiser
DOI:10.1055/s-1997-1025
日期:1997.11
The amount of osmium required for satisfactory levels of conversion and asymmetric induction in the AD reaction of 1-arylcyclohexenes has been established.
functionalization of styryl carbon-carbon double bonds with triflamide is described viadual visible-light photoredox/cobaloxime catalysis. A range of allylictriflamides (20 examples) were isolated in moderate to good yields (up to 88%) under stoichiometric acceptorless conditions. Dedicated labelling, as well as spectroscopic experiments, enabled to shed light on the concatenated photo- and chemo-catalytic cycles