Regioselective construction of six-membered fused heterocyclic rings via Pd/C-mediated C–C coupling followed by iodocyclization strategy: a new entry to 2H-1,2-benzothiazine-1,1-dioxides
作者:Deepak Kumar Barange、Venkateswara Rao Batchu、Dhillirao Gorja、Vijaya Raghavan Pattabiraman、Lakshmi Kumar Tatini、J. Moses Babu、Manojit Pal
DOI:10.1016/j.tet.2006.12.040
日期:2007.2
practical and elegant method of constructing a thiazine ring fused with benzene under mild reaction conditions. A variety of 4-iodo-2H-benzo[e][1,2]thiazine-1,1-dioxides were prepared with high regioselectivity via a two-step process involving Pd/C-mediated C–C coupling of o-halobenzenesulfonamides with terminal alkynes, followed by iodocyclization of the resulting o-(1-alkynyl)arenesulfonamide using elemental
我们描述了在温和的反应条件下构建与苯稠合的噻嗪环的实用而优雅的方法。通过Pd / C介导的邻位C-C偶联的两步法,以高区域选择性制备了各种4-碘-2 H-苯并[ e ] [1,2]噻嗪-1,1-二氧化物。卤代苯磺酰胺与末端炔烃,然后在乙腈中使用碘元素碘化生成的邻-(1-炔基)芳烃磺酰胺。在Et 3存在下,使用10%Pd / C–PPh 3 –CuI作为催化剂体系进行偶联反应N.该方法对于溴化物和碘化物效果很好,因此使用了各种各样的含有烷基和芳基取代基的末端炔烃。碘环化步骤容许各种官能团,例如羟基,氯,氰基和甲氧基,选择性地产生六元杂环。所得的4-碘-2 H-苯并[ e ] [1,2]噻嗪-1,1-二氧化物参与了Sonogashira,Heck和Suzuki反应,从而以高收率产生了多种功能取代的苯并噻嗪。