Tandem Reactions via Barton Esters with Intermolecular Addition and Vinyl Radical Substitution onto Indole
作者:Robert Coyle、Patrick McArdle、Fawaz Aldabbagh
DOI:10.1021/jo5008543
日期:2014.6.20
A one-pot initiator-free Barton ester decomposition with tandem radical addition onto alkyl propiolates or phenylacetylene with aromatic substitution of the resultant vinyl radical allows convenient access to new 9-substituted 6,7-dihydropyrido[1,2-a]indoles. Propyl radical cyclizations compete when forming the expanded 7,8-dihydro-6H-azepino[1,2-a]indole system. 2-Thiopyridinyl S-radical is incorporated
一锅式无引发剂的Barton酯分解反应,将自由基串联添加到丙炔酸烷基酯或苯乙炔上,并用芳香族取代所得的乙烯基,可以方便地获得新的9-取代的6,7-二氢吡啶并[1,2- a ]吲哚。丙基自由基环化在形成扩展的7,8-二氢-6 H-氮杂环庚烷[1,2- a ]吲哚体系时竞争。当使用未取代的吲哚-1-链烷酸前体时,将2-硫代吡啶基S-自由基结合到芳族加合物中。取代产物的X射线晶体学分析可以确定将自由基加成到反应性较低的内部炔烃上的选择性。