First Total Synthesis of the Cytotoxic Carbazole Alkaloid Excavatine-A and Regioselective Annulation to Pyrano[2,3-<i>a</i>]carbazoles and [1,4]Oxazepino[2,3,4-<i>jk</i>]carbazoles
作者:Christian Brütting、Olga Kataeva、Arndt W. Schmidt、Hans-Joachim Knölker
DOI:10.1002/ejoc.201700515
日期:2017.6.16
first total synthesis of the cytotoxic carbazole alkaloid excavatine-A. The carbazole framework was constructed through double C–H bond activation of a diarylamine by using our palladium(II)-catalyzed oxidative cyclization. Treatment of the intermediate 8-hydroxycarbazoles with prenal and different additives led either to pyrano[2,3-a]carbazoles or to [1,4]oxazepino[2,3,4-jk]carbazoles. The pyran annulation
我们描述了细胞毒性咔唑生物碱吉伐他汀-A的第一个全合成。咔唑骨架是通过使用我们的钯(II)催化的氧化环化作用,通过对二芳基胺的双CH键进行活化而构建的。用甲醛和其他添加剂处理中间体8-羟基咔唑可生成吡喃并[2,3- a ]咔唑或生成[1,4]恶唑并[2,3,4- jk ]咔唑。研究了吡喃环化,以确定取代方式,添加剂和反应时间对选择性的影响。