An efficient one-potsynthesis of 2H-pyranonaphthoquinone was achieved via a palladium-catalyzed C–H bondactivation/C–Cbond formation/intramolecular Tsuji–Trost reaction cascade. The unprecedented procedure exhibits excellent functional group tolerance, giving the target naphthoquinones in moderate to good isolated yields (40–88%) under mild reaction conditions. Scalable production of the product
Environmentally benign, one-pot synthesis of pyrans by domino Knoevenagel/6π-electrocyclization in water and application to natural products
作者:Ene Jin Jung、Byung Ho Park、Yong Rok Lee
DOI:10.1039/c0gc00265h
日期:——
In water medium, environmentally benign, facile, and efficient synthesis of pyrans was achieved in good yields by the reactions of a variety of cyclic 1,3-dicarbonyls with several α,β-unsaturated aldehydes. The key strategy was a formal [3+3] cycloaddition by domino Knoevenagel/6Ï- electrocyclization. This methodology was applied to the synthesis of biologically interesting pyranocoumarin, pyranoquinolinone, and pyranonaphthoquinone derivatives along with selected natural and non-natural products.
Concise Synthesis of (±)-Rhinacanthin A, Dehydro α-Lapachone, and β-Lapachone, and Pyranonaphthoquinone Derivatives
作者:Xue Wang、Ye Chen、Yong-Rok Lee
DOI:10.5012/bkcs.2011.32.1.153
日期:2011.1.20
β-Lapachone was synthesized in three steps from 4-methoxy-1-naphthol by benzopyran formation, catalytic hydrogenation, and Jones oxidation. As additional reactions, synthesis of pyranonaphthoquinone derivatives with the pyranokunthone B skeleton has been achieved in a single step from readily available 2-hydroxy-6-methoxy1,4-naphthoquinone and 2-hydroxy-7-methoxy-1,4-naphthoquinone.
(±)-rhinacanthin A 的简明合成通过脱氢-α-lapachone 的环氧化和化学和区域选择性还原分两步实现。脱氢-α-拉帕酮也分两步合成,从 4-甲氧基-1-萘酚开始,通过乙二胺二乙酸酯 (EDDA) 催化的苯并吡喃形成和 CAN 介导的氧化反应。β-Lapachone 由 4-methoxy-1-naphthol 通过苯并吡喃形成、催化氢化和琼斯氧化三个步骤合成。作为附加反应,从容易获得的 2-羟基-6-甲氧基1,4-萘醌和 2-羟基-7-甲氧基-1,4-萘醌一步即可合成具有吡喃醌 B 骨架的吡喃萘醌衍生物。