Unexpected formation of 1-aryl-2-aminoalcohols during reductions of the corresponding amides and nitriles
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| Year of publication | 2021 |
| Type | Appeared in Conference without Proceedings |
| MU Faculty or unit | |
| Citation | |
| Description | As a result of our long-term interest in developing H-bond donor organocatalysts, we have prepared many chiral non-racemic amine scaffolds by reducing the corresponding enantiopure amides1. For such transformations, sodium bis(2-methoxyethoxy)aluminum hydride (SMEAH) is often used as a safer alternative to LiAlH4. Interestingly, (S)-naproxamide subjected to the above reduction conditions provided a curious product, which was then identified as the respective 1,2-amino alcohol derivative2. We found out that, in general, amides and nitriles of aryl-alkanoic acids bearing at least one hydrogen atom at benzylic position exhibit a unique reactivity towards SMEAH under O2 atmosphere. The substrate scope of this process was examined on 30 entries. Even though the respective products were provided in moderate yields only, the simple operating procedure may serve as a direct and powerful entry to the sterically congested 1,2-amino alcohols that are difficult or laborious to prepare by other routes. The plausible mechanistic proposal for the observed results was given based on the isolation and identification of the stable intermediates and stereochemical evidence. The present method may open up attractive prospective routes for future developments in 18O-labeling strategies or stereoselective synthesis thereof. The reaction was applied to a synthesis of a potentially bioactive target. |
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