General methods for alkaloid synthesis via intramolecular [4 + 2] cycloaddition reactions of enamides. A new approach to the synthesis of Aspidosperma alkaloids
In this study, we achieved the first totalsynthesis of (+)-heteroplexisolideE. The synthetic highlights of our approach include a one-pot regioselective methylation method and the transformation of a β-methallyl alcohol moiety to a prenyl group using palladium-catalyzed hydrogenolysis.
The first intramolecular silene Diels–Alder reactions
作者:Michal Czyzewski、Jonathan D. Sellars、Tamaz Guliashvili、Julius Tibbelin、Lisa Johnstone、Justin Bower、Matthew Box、Robert D. M. Davies、Henrik Ottosson、Patrick G. Steel
DOI:10.1039/c3cc49526d
日期:——
The synthesis of silaheterocycles through the first examples of an intramolecular silene DielsâAlder reaction is described.
描述了通过首次实例的分子内硅烯Diels-Alder反应合成硅杂环化合物。
Photochemistry of α,α-disubstituted bicyclic cyclobutanones - a potential thermal-photochemical metathesis reaction
作者:Edward Lee-Ruff、Alan C. Hopkinson、Hira Kazarians-Moghaddam
DOI:10.1016/s0040-4039(00)81845-6
日期:1983.1
Under certain conditions the photolysis of α,α-disubstituted cyclobutanones give terminal olefinic esters. A two-stage thermal photochemical metathesis is described.
在某些条件下,α,α-二取代的环丁酮的光解反应可生成末端烯烃酯。描述了两阶段热光化学复分解。
Convenient Radical<b><i>α</i></b>-Monoallylations of Carbonyl Compounds
Free radical allylations of α-seleno carbonyl compounds with tributyl-substituted 2,4-pentadienyltin, 2-methyl-2-propenyltin, 2-butenyltin, and 3-methyl-2-butenyltin, are described. Such successful C–C bond formations, in particular with the 2-butenyltin and the 3-methyl-2-butenyltin, are owing to the high reactivity of the α-carbon radical, generated from α-seleno carbonyl compounds, toward allylic tin compounds.
Generation of the 7-Azabicyclo[4.3.1]decane Ring System via (4 + 3) Cycloaddition of Oxidopyridinium Ions
作者:Chencheng Fu、Steven P. Kelley、Jianzhuo Tu、Michael Harmata
DOI:10.1021/acs.joc.1c00032
日期:2021.5.21
Oxidopyridinium ions bearing an ester group at the 5-position undergo (4 + 3) cycloaddition reaction to afford congeners of 7-azabicyclo[4.3.1]decane. The reaction generally proceeds in high yield, although an excess of diene is often required to achieve such yields. The reaction is highly regioselective, but not endo/exo selective. It appears the cycloaddition process can be either kinetically or