An efficient method for the one-pot construction of the 1H-naphtho[2,3-c]pyran-5,10-dione system
作者:Kazuhiro Kobayashi、Masaharu Uchida、Tomokazu Uneda、Keiichi Yoneda、Miyuki Tanmatsu、Osamu Morikawa、Hisatoshi Konishi
DOI:10.1039/b106933k
日期:2001.11.15
2-(1-Hydroxyalkyl)-1,4-naphthoquinones are found to react with pyrrolidino enamines in toluene to give 1H-naphtho[2,3-c]pyran-5,10-diones in good yields via a tandem conjugate addition–cyclization sequence, followed by an elimination of pyrrolidine. 2-Hydroxymethyl-1,4-naphthoquinone and morpholino enamines undergo a similar sequence, without loss of morpholine, to yield 3-morpholino-3,4-dihydro-1H-naphtho[2,3-c]pyran-5,10-diones. The 3-morpholino group of these products can be replaced with a hydro, a hydroxy, or a methoxy group. Imines also react with 2-(1-hydroxyalkyl)-1,4-naphthoquinones to give the corresponding 1H-naphtho[2,3-c]pyran-5,10-diones, including a natural product (pentalongin). The utility of these reactions is demonstrated in the synthesis of pyranonaphthoquinone antibiotics, viz. (±)-eleutherin and (±)-isoeleutherin.
2-(1-羟基烷基)-1,4-萘醌与吡咯烯胺在甲苯中反应,通过串联的共轭加成-环化序列,高产率地生成1H-萼[2,3-c]吡喃-5,10-二酮,随后排除吡咯啉。2-羟基甲基-1,4-萘醌与吗啉烯胺经历类似的反应序列,且不损失吗啉,生成3-吗啉基-3,4-二氢-1H-萼[2,3-c]吡喃-5,10-二酮。这些产物的3-吗啉基可以被羟基、氢或甲氧基取代。亚胺也与2-(1-羟基烷基)-1,4-萘醌反应,生成对应的1H-萼[2,3-c]吡喃-5,10-二酮,包括一种天然产物(pentlongin)。这些反应的实用性在于合成了吡喃萘醌抗生素,如(±)-eleutherin和(±)-isoeleutherin。