1384273-45-3Relevant academic research and scientific papers
Model studies for a ring-closing metathesis approach to the bafilomycin macrolactone core from a 2,2-Dimethoxy tetraenic ester precursor
Chevalley, Alice,Prunet, Joelle,Mauduit, Marc,Ferezou, Jean-Pierre
, p. 8265 - 8278 (2013)
A ring-closing metathesis strategy is reported for the construction of the 16-membered macrolactone core of the bafilomycins. One decisive key feature is the presence of a 2,2-dimethoxyketal functionality at C-2 that provides the required flexibility to the tetraenic ester precursor, allowing the ring-closing metathesis reaction to take place. Three different model esters of increasing complexity were successfully subjected to the 1,3-diene-ene ring-closing metathesis reaction. The best promoter for the simplest esters was the Grubbs first-generation precatalyst. A Hoveyda-Grubbs-type trifluoromethylamido- containing precatalyst developed by Mauduit's group gave satisfactory results for the most complex ester. In all experiments, the 12-Z-configured isomer was obtained as the major product. Subsequent microwave-promoted methanol elimination was achieved on the simplest model compound using camphorsulfonic acid (CSA) as a catalyst. Under these conditions, a E to Z isomerization of the double bond at C-4, as well as ca. 50 % isomerization of the 12-Z double bond into the corresponding 12-E isomer, were observed. Thanks to the presence of a 2,2-dimethoxyketal functionality at C-2 of the ester precursors, models of the bafilomycin core were synthesized using a ring-closing metathesis strategy. An indenylidene Ru complex gave the best results for the ring-closing metathesis step on an advanced model ester. Finally, acid-catalysed elimination of MeOH yielded the required tetraenic macrolactone. Copyright
One-pot formation of aza-enolates from secondary amines and condensation to esters and alkyl bromides
Chevalley, Alice,Férézou, Jean-Pierre
experimental part, p. 5882 - 5889 (2012/09/11)
Starting from commercial secondary amines, a one-pot procedure allows a direct access to enaminones through a one-pot deprotonation/oxidation/in situ re-deprotonation/acylation sequence without intermediate isolation of the intermediate Schiff base or its corresponding enamine tautomer. An alternative one-pot sequence involving a similar oxidation step followed by one or two alkylation steps yields, after acidic work-up, functionalized ketones directly from the parent amine. This process has been applied to an expeditious synthesis of the male aggregation pheromone of the cereal leaf beetle Oulema melanopus.
