Fe(0)-Mediated Synthesis of Tri- and Tetra-Substituted Olefins from Carbonyls: An Environmentally Friendly Alternative to Cr(II)
作者:J. R. Falck、Romain Bejot、Deb K. Barma、Anish Bandyopadhyay、Suju Joseph、Charles Mioskowski
DOI:10.1021/jo061445u
日期:2006.10.1
carbonyls by activated polyhalides. In many instances, Fe(0) was equivalent or superior to Cr(II). Notably, Fe(0), but not Cr(II), proved compatible with a wide range of functionality, inter alia, unprotected phenol, aryl nitro, carboxylic acid, and alkyl nitrile. A surprising reversal of stereoselectivity for aldehydes versus ketones was observed using both metals. The resultant α-halo-α,β-unsaturated or α
An enantioselective alkoxycarbonylation-amination cascade process of terminalallenes with CO, methanol, and arylamines has been developed. It proceeds under mild conditions (room temperature, ambient pressure CO) via oxidative Pd(II) catalysis using an aromatic spiroketal-based diphosphine (SKP) as a chiral ligand and a Cu(II) salt as an oxidant and affords a wide range of α-methylene-β-arylamino
When heated in refluxing benzene or toluene, α-diazo β-ketophosphonates 2, prepared in three steps from aldehydes or ketones, gave rise to functionalized cyclobutenones 4 or phenolic compounds 5. These products are formed by electrocyclisation respectively of a vinyl or dienylketene, resulting from a Wolff rearrangement.
Photosensitized oxygenation of phenylpyruvic acid derivatives as a model for p-hydroxyphenylpyruvate dioxygenase
作者:Hiyoshizo Kotsuki、Isao Saito、Teruo Matsuura
DOI:10.1016/0040-4039(81)80128-1
日期:1981.1
Dye-sensitized photooxygenation of enol ethers of methyl phenylpyruvates () produced diendoperoxides in aprotic solvents, whereas in methanol hydroxylated product was obtained. The reaction scheme is discussed in comparison uith that for the enzymic transformation.
Synthesis of functionalized phenolic derivatives via the benzannulation of dienylketenes formed by a thermal wolff rearrangement of α-diazo-β-keto compounds
Eleven conjugated dienyl α-diazo-β-keto derivatives were prepared from α,β-unsaturated carbonyl compounds. Their thermolysis induced a Wolff rearrangement generating an intermediate dienyl ketene whose isomer which has the required configuration of the internal double bond underwent a benzannulation thus forming the corresponding phenolic derivatives. When γ-substituted by a methoxy group both stereoisomers