Novel syntheses of murrayaquinone A and furostifoline through 4-oxygenated carbazoles by allene-mediated electrocyclic reactions starting from 2-chloroindole-3-carbaldehyde.
Novel syntheses of murrayaquinone A and furostifoline through 4-oxygenated carbazoles by allene-mediated electrocyclic reactions starting from 2-chloroindole-3-carbaldehyde.
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以 2-氯吲哚-3-甲醛为起始原料，通过丙二烯介导的电环反应，通过 4-氧化咔唑合成九里醌 A 和呋替叶林。
DOI：
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发表时间：
2001
影响因子：
1.7
通讯作者：
S. Hibino
中科院分区：
文献类型：
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作者：
Hitomi Hagiwara;T. Choshi;Junko Nobuhiro;Hiroyuki Fujimoto;S. Hibino
以2-氯吲哚-3-甲醛（11）为起始原料，通过2-烯基-3-炔丙基吲哚（9）衍生的2-烯基-3-烯丙基吲哚（8）的新型电环化反应，构建了4-含氧的3-甲基咔唑（7），完成了Murrayaquinone A（1）的全合成和呋豆叶林（5）的全合成。16 c和22的N，O-双苄氧基甲基进行Birch还原，然后用Triton B处理，以产生已知的4-羟基-3-甲基咔唑（7 a）和4-羟基-3-甲基呋喃并[3，2-a]咔唑（7 B），分别作为Murrayaquinone A（1）和furosifoline（5）的前体。将由7 b制备的三氟甲磺酰氧基-3-甲基呋喃并[3，2-a]咔唑（24）进行还原裂解以提供呋豆叶林（5）。
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 and 22 underwent a Birch reduction followed by treatment with Triton B to produce the known 4-hydroxy-3-methylcarbazole (7a) and 4-hydroxy-3-methylfuro[3,2-a]carbazole (7b) as precursors of murrayaquinone A (1) and furostifoline (5), respectively. The trifluoromethanesulfonyloxy-3-methylfuro[3,2-alcarbazole (24), prepared from 7b, was subjected to reductive cleavage to provide furostifoline (5).