A cyanide‐free platform technology for the synthesis of chiral nitriles by biocatalytic enantioselective dehydration of a wide range of aldoximes is reported. The nitriles were obtained with high enantiomeric excess of >90 % ee (and up to 99 % ee) in many cases, and a “privileged substrate structure” with respect to high enantioselectivity was identified. Furthermore, a surprising phenomenon was observed
was also eliminated by the addition of 2 equivalents of water to the reaction system. The reduction was applied to the syntheses of precursors of such anti-inflammatory agents as ibuprofen, butibufen, naproxen, and related compounds, as well as (±)-ar-turmerone, an odorous sesquiterpene.
[cyano, nitro, (non)enolizable ketone, chloride, and amide moieties] are allowed on methoxyarenes. Moreover, an array of alkanenitriles with/without an aryl moiety at the nitrile α-position can be employed. The system also features no requirement of a stoichiometric base, MeOH (not salt waste) formation as a byproduct, and the production of congested quaternary carbon centers.
Lithiated 2-arylpropionitriles were found to react with selenium and carbon monoxide under mild conditions to yield lithium selenocarboxylates. Subsequent alkylation of the selenocarboxylates with methyl iodide gave the corresponding selenol esters in good to high yields.
Rhenium(I)-Catalyzed C-Methylation of Ketones, Indoles, and Arylacetonitriles Using Methanol
作者:Sujan Shee、Sabuj Kundu
DOI:10.1021/acs.joc.1c00376
日期:2021.5.7
A ReCl(CO)5/MeC(CH2PPh2)3 (L2) system was developed for the C-methylation reactions utilizing methanol and base, following the borrowing hydrogen strategy. Diverse ketones, indoles, and arylacetonitriles underwent mono- and dimethylation selectively up to 99% yield. Remarkably, tandem multiple methylations were also achieved by employing this catalytic system.