A novel synthetic protocol for the synthesis of <i>pulvinones,</i> and naturally occurring <i>Aspulvinone E</i>, molecules of medicinal interest
作者:Kyriakos C. Prousis、Sotirios Katsamakas、John Markopoulos、Olga Igglessi-Markopoulou
DOI:10.1080/00397911.2021.2001662
日期:2022.1.2
Abstract A novel two step methodology for readily accessible natural “pulvinone” derivatives in excellent yields has been developed starting from activated precursors, bearing a functionalized 1,3-dioxolane-2,4-diones (OCA’s), as dually protected-activated synthons of α-hydroxy acids. The present procedure is based on a tandem C-acylation-cyclization process under mild conditions with good yields.
Tandem Claisen Condensation/Transesterification between Arylacetate Enolates and Arylmethylene-Substituted 2,2-Dimethyl-1,3-dioxolan-4-ones: An Improved Synthesis of <i>Z</i>-Configured Pulvinones
作者:Reinhard Brückner、Natasza Kaczybura
DOI:10.1055/s-2006-950378
日期:2007.1
Horner-Wadsworth-Emmons (HWE) alkenations of aromatic aldehydes with the novel phosphonate 24b led to E-configured arylmethylene-substituted 2,2-dimethyl-1,3-dioxolan-4-ones 25a-f (79-88% yield). The latter condensed with the lithium enolates of methyl arylacetates lithio-20b-d to give, after acid treatment and crystallization, isomerically pure (Z)-pulvinones 8d-s in 75-91% yield. We also showed that Horner-Wadsworth-Emmons reactions between phosphonate 24b and aliphatic aldehydes lead to E-configured alkylmethylene-substituted 2,2-dimethyl-1,3-dioxolan-4-ones 25g-i (82-96% yield).
Synthesis of pulvinones via tandem Dieckmann condensation–alkoxide β-elimination
作者:Brice Nadal、Julien Rouleau、Hélène Besnard、Pierre Thuéry、Thierry Le Gall
DOI:10.1016/j.tet.2011.02.011
日期:2011.4
A series of pulvinones were prepared in three steps from a common precursor, methyl 3-phenylglycidate. This compound was readily converted to several diesters containing an ether function. Then, treatment of these compounds with lithium hexamethyldisilazide afforded the corresponding pulvinones, via tandem Dieckmann condensation-alkoxide beta-elimination. The use of a 2,2,2-trifluoroethyl ether instead of a methyl ether facilitated the beta-elimination and led to better yields of product. (C) 2011 Elsevier Ltd. All rights reserved.
Novel Synthesis of Naturally Occurring Pulvinones: A Heck Coupling, Transesterification, and Dieckmann Condensation Strategy
作者:Reinhard Brückner、David Bernier
DOI:10.1055/s-2007-983803
日期:2007.7
diimide activated arylacetic acids yielded the isomerically pure trifluoro-ethyl ( Z)-2-(arylacetoxy)cinnamates 38A- O. These were excellent substrates of potassium TERT-butoxide mediated Dieckmanncondensations, and distinctly superior to fluorine-free analogues, furnishing Z-configured pulvinones 1A- O ( 1I = aspulvinone A). Cleavage of the aryl ether moieties of pulvinones 1D, E, H, N, O provided
碘芳烃与 2-乙酰氧基丙烯酸三氟乙酯 (19) 的无膦 Heck 烯基化反应立体选择性地生成三氟乙基 (Z)-2-乙酰氧基肉桂酸酯 31-34、42、44 和 51。脱乙酰化后用 N,N'-二环己基碳二亚胺酰化活化的芳基乙酸产生异构纯的三氟乙基 (Z)-2-(芳基乙酰氧基)肉桂酸酯 38A-O。这些是叔丁醇钾介导的 Dieckmann 缩合的优良底物,并且明显优于无氟类似物,提供 Z 构型pulvinones 1A-O (1I = aspulvinone A)。pulvinones 1D、E、H、N、O 的芳基醚部分的裂解提供 aspulvinone E (1R)、aspulvinone G (1S)、3',4,4'-trihydroxypulvinone (1V) 和 aspulvinones B (1X) 和H (1Y),分别。2的转换,