Aldol additions of pinacolone lithium enolate with ketones: reactivities governed predominantly by field effects
作者:Goutam Das、Edward R. Thornton
DOI:10.1021/ja00057a012
日期:1993.2
The relative reactivities of representative α- and β-heterosubstituted acyclic, cyclic (five- and six-membered), and aromatic ketones with the lithiumenolate of pinacolone in diethyl ether at -78 o C were determined. The order of reactivitiesof monosubstituted acetones (MeCOCH 2 X) is X=Cl>OTBDMS>OMe>SMe>NMe 2 >CH 2 SM>H>Me and spans a range of 10 4
测定了代表性的 α- 和 β- 杂取代的无环、环状(五元和六元)和芳香酮与频哪酮的烯醇锂在 -78 o C 的二乙醚中的相对反应性。单取代丙酮 (MeCOCH 2 X) 的反应性顺序为 X=Cl>OTBDMS>OMe>SMe>NMe 2 >CH 2 SM>H>Me,范围为 10 4
Erzeugung und cycloaddition von allyliumionen aus α-halogenketonen unter solvolyse-bedingungen
Some α-haloketones react with furan in methanolic solution in the presence of base to form the 3-oxo-8-oxabicyclo[3.2.1]oct-6-enes (), the products derived from a [4+3] cycloaddition of an allylium intermediate ( or ).
Regiochemical Studies of the Ring Expansion Reactions of Hydroxy Azides with Cyclic Ketones
作者:Brenton T. Smith、Vijaya Gracias、Jeffrey Aubé
DOI:10.1021/jo000056b
日期:2000.6.1
The regiochemistry of ringexpansions of 2-substituted cyclicketones using 1,2-azidoethanol and 1,3-azidopropanol was examined. It was determined that the reactions of ketones with an adjacent methyl or ethyl group are generally unselective, but that bulkier substituents lead to preferential migration of the more highly substituted carbon. In addition, it was found that ketones bearing inductively
α-Methoxyketone synthesis via ketone homologation: ZrCl<sub>4</sub>-mediated hydroxy sulfone rearrangements
作者:John G. Montana、Neil Phillipson、Richard J. K. Taylor
DOI:10.1039/c39940002289
日期:——
The adducts between ketones and the anion derived from [(methoxymethyl)sulfonyl]benzene undergo efficient, regioselective rearrangement to give α-methoxyketones when treated with ZrCl4 and HfCl4; this new procedure allows the sulfone-mediated homologation methodology to be applied to monocyclic and acyclic ketones.
Ketone homologation to produce α-methoxyketones: application to conduritol synthesis
作者:Neil Phillipson、Michael S. Anson、John G. Montana、Richard J. K. Taylor
DOI:10.1039/a703073h
日期:——
The scope of Trost’s sulfone homologation procedure for the conversion of ketones into their α-methoxylated higher homologues has been dramatically expanded. The use of zirconium (or hafnium) tetrachloride in the hydroxy sulfonerearrangement step gives good yields with the adducts of aryl alkyl ketones, dialkyl ketones and cycloalkanones, and the rearrangement occurs with total regioselectivity. Mechanistic