Novel Syntheses of Murrayaquinone A and Furostifoline through 4-Oxygenated Carbazoles by Allene-Mediated Electrocyclic Reactions Starting from 2-Chloroindole-3-carbaldehyde.
作者:Hitomi HAGIWARA、Tominari CHOSHI、Junko NOBUHIRO、Hiroyuki FUJIMOTO、Satoshi HIBINO
DOI:10.1248/cpb.49.881
日期:——
The formal total synthesis of murrayaquinone A (1) and the total synthesis of furostifoline (5) were completed by the construction of 4-oxygenated 3-methylcarbazoles 7 based on a new type of electrocyclic reaction through 2-alkenyl-3-allenylindole intermediates 8 derived from the 2-alkenyl-3-propargylindoles 9, starting from 2-chloroindole-3-carbaldehyde (11). The N,O-bisbenzyloxymethyl group of 16c
通过基于2-烯基-3-烯丙基吲哚中间体的新型电环反应,通过构建4-氧化的3-甲基咔唑7,完成了正式的全合成Murrayaquinone A(1)和呋喃噻吩啉(5)合成8衍生自2-烯基-3-炔丙基吲哚9,起始于2-氯吲哚-3-甲醛(11)。对16c和22的N,O-双苄氧基甲基进行Birch还原,然后用Triton B处理以生产已知的4-羟基-3-甲基咔唑(7a)和4-羟基-3-甲基呋喃[3,2-a]咔唑(7b)分别作为Murrayaquinone A(1)和Furostifoline(5)的前体。将由7b制得的三氟甲磺酰氧基-3-甲基呋喃[3,2-alcarbazole](24)进行还原裂解,得到呋喃噻啉(5)。