Synthesis of cyclopropyl silyl ethers and their facile ring opening by photoinduced electron transfer as key step in radical/radical cationic cascade reactions
作者:Prashant A. Waske、Jochen Mattay
DOI:10.1016/j.tet.2005.08.034
日期:2005.10
Various ring-fused cyclopropyl silyl ethers with an benzylic, olefinic or acetylenic side chain have been synthesized. Upon oxidative photoinducedelectrontransfer (PET) the cyclopropane ring opens and forms a reactive β-keto radical, which undergoes intramolecular cyclization. In some cases we observed only formation of ring opened non-cyclized products. With olefinic side chain 5-exo-trig mode of
作者:Steven W. M. Crossley、Francis Barabé、Ryan A. Shenvi
DOI:10.1021/ja5105602
日期:2014.12.3
Catalytic amounts of Co(SaltBu,tBu)Cl and organosilane irreversibly isomerize terminal alkenes by one position. The same catalysts effect cycloisomerization of dienes and retrocycloisomerization of strained rings. Strong Lewis bases like amines and imidazoles, and labile functionalities like epoxides, are tolerated.
Copper-catalyzed oxidative aromatization of 2-cyclohexen-1-ones to phenols in the presence of catalytic hydrogen bromide under molecular oxygen
作者:Kotaro Kikushima、Yuta Nishina
DOI:10.1039/c3ra43071e
日期:——
Catalytic oxidative aromatization has been achieved using 2-cyclohexen-1-ones to obtain phenol derivatives in the presence of a catalytic amount of copper salt and aqueous HBr under molecular oxygen. The amount of HBr was successfully reduced to a catalytic quantity, and the other additive such as a ligand and an oxidant as well as inert conditions were unnecessary. Various mono-, di-, and trisubstituted
Photoinduced electron transfer (PET) reactions of α-cyclopropyl-substituted ketones and triethylamine (TEA) were used to initiate the cyclopropylcarbinyl-homoallyl rearrangement. The intramolecular cyclization reaction onto triple bonds was performed yielding bicyclic and spirocyclic compounds. Furthermore, in some preliminary studies it was shown that even intramolecular aromatic substitutions are
A new synthon for the regiospecific γ-alkylation of 2-cyclohexenones. Application to the synthesis of zingiberenol and oxygenated bicycle[3.3.1] nonanes
作者:Leo A. Paquette、William A. Kinney
DOI:10.1016/s0040-4039(00)86766-0
日期:——
The regiospecific γ-alkylation of γ-sulfonycyclohexone ketals is described and applied to variuos synthetic objectives.