2,3-取代的 4-氯-2-环丁烯酮,由取代的环丁烯二酮的区域特异性转化制备,经过钯催化与乙烯基和芳基锡烷以及乙烯基锆试剂交叉偶联,形成 4-R unsat -2-环丁烯酮。在热解 (100 o C) 时,这些底物以高产率转化为取代的苯酚。使用这种化学方法以区域特异性方式制备了五取代的芳香族化合物和各种三取代和四取代的芳香族化合物
2,3-取代的 4-氯-2-环丁烯酮,由取代的环丁烯二酮的区域特异性转化制备,经过钯催化与乙烯基和芳基锡烷以及乙烯基锆试剂交叉偶联,形成 4-R unsat -2-环丁烯酮。在热解 (100 o C) 时,这些底物以高产率转化为取代的苯酚。使用这种化学方法以区域特异性方式制备了五取代的芳香族化合物和各种三取代和四取代的芳香族化合物
A photochemical ring expansion of 6- to 8-membered nitrogen heterocycles by [1,3]-sigmatropic rearrangement
作者:Morgan A. Manning、Wei Sun、Mark E. Light、David C. Harrowven
DOI:10.1039/d1cc00393c
日期:——
route to azocines and benzoazocines from furopyridinones is described through a photochemically induced [1,3]-sigmatropic rearrangement. The method gives access to these 8-membered nitrogen heterocycles from dimethyl squarate in four stages and with excellent atom economy by sequencing thermal and photochemicalringexpansion steps under continuous flow.
Synthesis of .alpha.-Pyridone-Based Azaheteroaromatics by Intramolecular Vinylketene Cyclizations onto the C:N Bond of Nitrogen Heteroaromatics
作者:Angela Gurski Birchler、Fuqiang Liu、Lanny S. Liebeskind
DOI:10.1021/jo00104a033
日期:1994.12
Substituted quinolizin-4-ones and ring-fused alpha-pyridone derivatives have been synthesized by the construction of 2,3-disubstituted-4-(2-azaheteroaryl)-2-cyclobutenones followed by thermal rearrangment. 4-(2-Azaheteroaryl)-2-cyclobutenones have been prepared regioselectively by the addition of 2-lithioazaheteroaromatics to cyclobutenediones and by palladium catalyzed cross-coupling of 4-chloro-2-cyclobutenones with 2-tri-n-stannylazaheteroaromatics. The thermal transformation is proposed to occur by ring-opening of the cyclobutenone followed by intramolecular cyclization of the transient vinylketene onto the carbon-nitrogen double bond of the azaheteroaromatic. A variety of quinolizin-4-ones, imidazo [1,2-a]pyridin-5-ones, 1-oxopyrido[2,1-b]benzothiazoles, and thiazolo[3,2-a]pyridin-5-ones were prepared.