Condensation of Dimethyl 1,3‐Acetonedicarboxylate with 1,2‐Dicarbonyl Compounds: cis ‐bicyclo[3.3.0]octane‐3,7‐diones

Abstract

Condensation of Dimethyl 1,3‐Acetonedicarboxylate with 1,2‐Dicarbonyl Compounds: cis ‐Bicyclo[3.3.0]octane‐3,7‐diones intermediate: Tetramethyl 3,7‐dihydroxybicyclo[3.3.0]octa‐2,6‐diene‐2,4,6,8‐tetracarboxylate product: cis‐Bicyclo[3.3.0]octane‐3,7‐dione intermediate: Tetramethyl 3,7‐dihydroxy‐1,5‐dimethylbicyclo[3.3.0]octa‐2,6‐diene‐2,4,6,8‐tetracarboxylate product: cis‐1,5‐Dimethylbicyclo[3.3.0]octane‐3,7‐dione intermediate: C16H16O10Na2·H2O

C−C versus C−O Anionic Domino Cycloalkylation of Stabilized Carbanions: Facile One-Pot Stereoselective Preparation of Functionalized Bridged Bicycloalkanones and Cyclic Enol Ethers

“…Alternatively, more complex bridged tetra-or hexacyclic structures 3 i, j could also be reached selectively starting from readily available Weiss tetraester 1 b [17] (Scheme 2). While 3 j Scheme 2.…”

3-Azatetracyclo[5.2.1.15,8.01,5]undecane Derivatives: From Wild-Type Inhibitors of the M2 Ion Channel of Influenza A Virus to Derivatives with Potent Activity against the V27A Mutant

“…Thus, we synthesized diacids 12c,d from easily available diketones 17c,d, following the synthetic sequence shown in Scheme 2 that we had previously developed for related bisnoradamantane derivatives. 27 To homologate diketones 17c-d, [28][29][30] they were transformed into a mixture of the corresponding bis-vinyl iodides syn-and anti-19c-d, via the corresponding bis-hydrazones, 18c-d, following the Barton procedure, in 41 and 56%, respectively, overall yield. [31][32] Then, palladium (0) catalyzed methoxycarbonylation of 19c-d afforded 20c-d in 62 and 64% yield, respectively, as a mixture of syn and anti regioisomers.…”

Ytterbium triflate (and trimethylsilyl triflate) catalyzed isomerization of glycidic esters to α-hydroxy-β,γ-unsaturated esters and their conversion into cyclopentanoids using Johnson-Claisen rearrangement

“…In an attempt to make use of this type of cyclopentanoid formation in the synthesis of tricyclopentanoids, the bicyclo (3.3.0) system 23 20 was converted into the corresponding diester 27 via the same sequence of reactions as described above (Scheme-2), however, it did not undergo cyclization to form the tricyclopentanoid systems 28/29 possibly again due to the resultant trans geometry at the junction after hydrogenation. If reduction of the double bond leads to a cis junction, it is possible to make use of the present methodology for the synthesis of tricyclopentanoids.…”