Diels-Alder reactions of fused 5-, 6- and 7-membered ring 2-vinylindoles: Synthesis of annulated tetrahydrocarbazoles
作者:Wayland E. Noland、Ryan J. Herzig、Honnaiah Vijay Kumar、Venkata Srinivasarao Narina、Pavel K. Elkin、Karen I. Valverde、Briana L. Kim
DOI:10.1016/j.tet.2017.09.025
日期:2017.11
fused 5-, 6- and 7-membered ring 2-vinylindoles and various dienophiles. The dienophiles used were N-phenylmaleimides, 1,4-naphthoquinone, and dimethyl acetylenedicarboxylate (DMAD). When 1,4-naphthoquinone was used as a dienophile, the 5-membered ring Diels-Alder adduct was obtained in the oxidized form, but this form was not observed in the case of 6- and 7-membered ring Diels-Alder adducts. The desired
四氢咔唑的支架是一类重要的生物活性化合物,存在于自然界中。在本研究中,使用稠合的5、6和7元环2乙烯基吲哚与各种亲二烯体之间的Diels-Alder环加成反应合成了功能化的多环四氢咔唑。所用的亲双烯体是N-苯基马来酰亚胺,1,4-萘醌和乙炔二羧酸二甲酯(DMAD)。当将1,4-萘醌用作亲二烯体时,以氧化形式获得了5元环Diels-Alder加合物,但是在6元和7元环Diels-Alder加合物的情况下未观察到该形式。所需产物的收率范围为60-70%,使用1D和2D NMR分析确定最终化合物的结构。1个1 H NMR研究证实了极好的非对映选择性(> 99%de)。