在尝试通过酸催化的分子内炔烃羰基复分解反应构建10-酰基-5 H-苯并[ e ]吡咯并[1,2- a ]氮杂环庚烷时,发现两种独特的环化方式取决于反应温度。5 ħ -苯并[ ë ]吡咯并[1,2一]获得具有在C11位置的取代基氮杂-1- carbaldehydes作为主要产物在90℃下为分子内7-结果内切挖环化,而6 -内挖在某些情况下,在40°C时观察到在酸性介质下亲电将吡咯的氮加成至乙烯基阳离子上,然后进行空前的多米诺骨牌重排过程,从而导致闭环,从而生成5-芳基-11 H-苯并[ d ]吡咯并[ 1,2- a ]氮杂-1-甲醛与以前的产品。
Carbopalladation/Suzuki Coupling Cascade for the Generation of Quaternary Centers: Access to Pyrrolo[1,2-<i>b</i>]isoquinolines
作者:Iratxe Barbolla、Nuria Sotomayor、Esther Lete
DOI:10.1021/acs.joc.9b01357
日期:2019.8.16
A convergent route to pyrrolo[1,2-b]isoquinolines with a quaternary center at C-10 has been developed, which implies a sequential Pd(0)-catalyzed carbopalladation followed by cross-coupling reaction with boronic acids. The adequate catalytic system and experimental conditions, with and without the use of phosphane ligands, have been selected to control the chemoselectivity of the process, allowing
已经开发了一条以四元中心在C-10上的吡咯并[1,2- b ]异喹啉的收敛途径,这意味着先后顺序是Pd(0)催化的碳钯反应,然后与硼酸进行交叉偶联反应。选择了适当的催化体系和实验条件,可以选择使用或不使用膦配体来控制该过程的化学选择性,从而使6-exo-carbopalladation生成四元中心并避免直接的Suzuki偶联。可以使用多种富电子和缺电子的芳基硼酸,以中等至良好的产率(最高94%,22个例子)为取代的吡咯并[1,2- b ]异喹啉提供有效的途径。
Synthesis of Benzo-fused Heterocycles by Intramolecular α-Arylation of Ketone Enolate Anions
作者:Javier F. Guastavino、Roberto A. Rossi
DOI:10.1021/jo202012n
日期:2012.1.6
benzo-fused heterocycles in good to excellent yields is reported. The synthetic strategy involves the generation of a new intramolecular α-aryl ketone bond by the photostimulated SRN1 reaction of ketone enolate anions linked to a pendant haloarene as the key step. On the other hand, an intramolecular CAr–CAr coupling led to the formation of five- and six-member benzo-fused heterocycles (9H-carbazole
据报道,六元,七元,八元和九元苯并稠合的杂环可以两步合成,产率高到极好。合成策略涉及通过与末端卤代芳烃连接的酮烯酸酯阴离子的光刺激S RN 1反应生成新的分子内α-芳基酮键。另一方面,当竞争性形成芳香酰胺阴离子时,分子内C Ar –C Ar偶联导致五元和六元苯并稠合杂环(9 H-咔唑和菲啶)的形成。