methyl acrylate utilizing a chiral Zn(II)/Mg(II) bimetallic template with low catalyst loading was successfully achieved. The bimetallic Lewis acid template derived from (R)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-bi-2-naphthol catalyzed the Diels–Alder reaction in the presence of molecular sieves 4 Å to afford various functionalized bicyclic γ-lactones with high enantiomeric purities.
Intramolecular diels-alder reactions of silyl acetal-tethered trienes
作者:Peter J. Ainsworth、Donald Craig、John C. Reader、Alexandra M.Z. Slawin、Andrew J.P. White、David J. Williams
DOI:10.1016/0040-4020(95)00721-j
日期:1995.10
The synthesis and intramolecularDiels-Alderreactions of a series of silyl acetal-tetheredtrienes 4–9 are described. The cycloadditions show complete regioselectivity, and in all but one case give exclusively cis-fused bicyclic products. The selectivities are rationalised in terms of stereoelectronic and steric effects.
Catalytic reductive [4 + 1]-cycloadditions of vinylidenes and dienes
作者:You-Yun Zhou、Christopher Uyeda
DOI:10.1126/science.aau0364
日期:2019.2.22
Five-membered rings for two nickels The Diels-Alder reaction is widely used to make six-membered rings by adding four-carbon dienes to two-carbon alkenes. It would seem straightforward to likewise access five-membered rings from dienes and one-carbon sources, or carbenes, but that does not tend to work. Instead, the carbene adds to just half of the diene to form a cyclopropane. Zhou and Uyeda now show
Zur kenntnis des Fuerstions; Synthesen alkylsubstituierter Phtalsäuren
作者:J. S. Scarpa、M. Ribi、C. H. Eugster
DOI:10.1002/hlca.19660490206
日期:1966.3.10
Der diterpenoide Blattfarbstoff Fuerstion aus Fuerstia africana T. C. E. Fries lieferte bei der energischen Oxydation mittels HNO3 Mellophansäure und substituierte Phtalsäuren, von denen zwei als 4-Methyl-3-(2′-carboxyäthyl)-phtalsäure 2A bzw. 4-Methyl-3-(3′-carboxypropyl)-phtalsäure 3A strukturell aufgeklärt wurden. Es werden die Synthesen von 2A, von 3-Methyl-6-(2′-carboxyäthyl)-phtalsäure 6, von
明镜diterpenoide Blattfarbstoff Fuerstion AUS Fuerstia AFRICANA TCE弗里斯lieferte贝DER energischen Oxydation mittels HNO 3 MellophansäureUND substituiertePhtalsäuren,冯田园ZWEI ALS 4-甲基-3-(2'-carboxyäthyl)-phtalsäure 2A bzw. 4-甲基-3-(3'-羧基丙基)-phtalsäure 3A strukturellaufgeklärtwurden。ES werden死Synthesen冯2A,冯·3-甲基-6-(2'-carboxyäthyl)-phtalsäure 6,冯·3-甲基-4-(2'-carboxyäthyl)-phtalsäure 17 UND冯verwandten Verbindungen
An Approach towards the Synthesis of the Spiroimine Fragment of 13-Desmethylspirolide C and Gymnodimine A
A general access to the spiroimine skeleton of gymnodimine and spirolides is described, relying on the construction of the cyclohexene fragment using an enantiocontrolled Diels–Alder reaction, the installation of the all‐carbon quaternary stereocenter through a stereocontrolled alkylation or aldolisation and the elaboration of the lateral chains at C7 and C22 using Wittig–Horner olefinations. The spiroimine