Regiodivergent Hydration–Cyclization of Diynones under Gold Catalysis
作者:Marta Solas、Miguel A. Muñoz、Samuel Suárez-Pantiga、Roberto Sanz
DOI:10.1021/acs.orglett.0c02892
日期:2020.10.2
Skipped diynones, efficiently prepared from biomass-derived ethyl lactate, undergo a tandem hydration–oxacyclization reaction under gold(I) catalysis. Reaction conditions have been developed for a switchable process that allows selective access to 4-pyrones or 3(2H)-furanonesfrom the same starting diynones. Further application of this methodology in the total synthesis of polyporapyranone B was demonstrated
Synthesis and Enantioselective Baeyer-Villiger Oxidation of Prochiral Perhydro-pyranones with Recombinant<b>
<i>E. coli</i>
</b>Producing<b>
<i>Cyclohexanone Monooxygenase</i>
</b>
作者:Marko D. Mihovilovic、Florian Rudroff、Wolfgang Kandioller、Birgit Grötzl、Peter Stanetty、Helmut Spreitzer
DOI:10.1055/s-2003-42035
日期:——
Recombinant whole cells of Escherichia coli overex-pressing Acinetobacter sp. NCIMB 9871 cyclohexanonemonooxygenase (E.C. 1.14.13.22) have been utilized for the Baeyer-Villiger oxidation of prochiral perhydro-pyranones. The spatial limitations of the enzyme's active site have been estimated by increasing the chain length of cis-substituents in positions 2 and 6. A diastereoselective synthetic sequence
Synthesis of γ-pyrones via decarboxylative condensation of β-ketoacids
作者:Jérémy Merad、Thomas Maier、Catarina A. B. Rodrigues、Nuno Maulide
DOI:10.1007/s00706-016-1851-2
日期:2017.1
AbstractThis manuscript describes the convergent synthesis of aryl- and alkyl-disubstituted γ-pyrones from β-ketoacids. The reaction proceeds in the presence of trifluoromethanesulfonic anhydride via an unprecedented decarboxylative auto-condensation of the starting material. Herein, the scope and limitations of this transformation are reported. Graphical abstract
Diastereoselective Synthesis of cis-2,6-Disubstituted Perhydro-4-pyranones Using Elevated Pressure Hydrogenation
作者:Marko D. Mihovilovic、Helmut Spreitzer
DOI:10.1007/s00706-005-0317-8
日期:2005.7
A diastereoselective strategy for the synthesis of gamma-pyrons was developed, starting from the Mg diacetonedicarboxylate complex. Initial cyclization with suitable anhydrides or acid chlorides, followed by hydrolytic decarboxylation leads to 2,6-disubstituted pyrans. Elevated pressure hydrogenation using Pd/C affords the title compounds in high diastereoselectivity. Scope and limitations of the method are outlined on selected examples.