pentynones 8a-f undergo anionic addition reactions of the resulting enolate species to the alkyne moiety and afford the 2,5-disubstituted furans 10a-f in yields ranging from 10-91%. The proposed mechanism involves the 2-methylene-dihydrofurans 11 as intermediates which tautomerize to yield the observed products. In the case of the α-picolyl derivative 8g both possible enolates 12 and 13 are formed which are
Studies on the synthesis of furans by anionic cyclization of 4-pentynones
作者:Ralf Vieser、Wolfgang Eberbach
DOI:10.1016/0040-4039(95)00785-b
日期:1995.6
The synthesis of 5-substituted 2-carbomethoxymethyl-furans 4 is achieved by base promoted cyclization of the 4-pentynones 3a-e which are easily accessible from the 4-pentynal 1.
TSUBOI SADAO; MIMURA SHIGETOSHI; ONO SHIN-ICHIRO; WATANABE KENJI; TAKEDA +, BULL. CHEM. SOC. JAP., 60,(1987) N 5, 1807-1812
作者:TSUBOI SADAO、 MIMURA SHIGETOSHI、 ONO SHIN-ICHIRO、 WATANABE KENJI、 TAKEDA +
DOI:——
日期:——
Unified Approach to Furan Natural Products via Phosphine‐Palladium Catalysis
作者:Violet Yijang Chen、Ohyun Kwon
DOI:10.1002/anie.202015232
日期:2021.4.12
the construction of tetraalkyl furans remains non‐trivial. The prevalence of alkyl groups in bioactive furan natural products, combined with the desirable bioactivities of tetraalkyl furans, calls for a general synthetic protocol for polyalkyl furans. This paper describes a Michael–Heck approach, using sequential phosphine‐palladium catalysis, for the preparation of various polyalkyl furans from readily
Exploitation of chemical predisposition in synthesis: an approach to the manzamenones
作者:Saleh Al-Busafi、Jeremy R. Doncaster、Michael G. B. Drew、Andrew C. Regan、Roger C. Whitehead
DOI:10.1039/b110829h
日期:2002.2.6
Full details of the syntheses of manzamenones A, C and F are reported, using an approach modelled on a plausible biogenetic theory. The key step of the approach is a “one-pot” conversion of the antileukemic cyclopentenone, untenone A, to manzamenone A which occurs in reasonable yield and which proceeds via a reaction sequence of dehydration, Diels–Alder dimerisation and retro-Dieckmann reaction. The synthetic approach has also been applied to the preparation of a number of shorter alkyl chain analogues of the natural products. Using a combination of NMR and X-ray crystallographic data for the shorter alkyl chain analogues of manzamenone A, it is suggested that the relative stereostructures of the majority of the manzamenones should be revised such that the acyl group at the C2 position lies on the α-face and that at the C5 position resides on the β-face.
报道了使用基于合理的生物遗传学理论的方法合成曼扎门酮 A、C 和 F 的完整细节。该方法的关键步骤是将抗白血病环戊烯酮untenone A“一锅”转化为manzamenone A,其收率合理,并通过脱水、Diels-Alder二聚和逆Dieckmann反应的反应顺序进行。该合成方法也已应用于制备许多天然产物的较短烷基链类似物。结合 NMR 和 X 射线晶体学数据来了解曼扎烯酮 A 的较短烷基链类似物,建议应修改大多数曼扎烯酮的相对立体结构,使得 C2 位上的酰基位于 α 上。 -面,C5 位置处的位于 β 面上。