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Gruzdev DA, Vakarov SA, Korolyova MA, Bartashevich EV, Tumashov AA, Chulakov EN, Ezhikova MA, Kodess MI, Levit GL, Krasnov VP. Acylative kinetic resolution of racemic methyl-substituted cyclic alkylamines with 2,5-dioxopyrrolidin-1-yl ( R)-2-phenoxypropanoate. Org Biomol Chem 2022; 20:862-869. [PMID: 35006228 DOI: 10.1039/d1ob02099d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The diastereoselective acylation of a number of racemic methyl-substituted cyclic alkylamines with active esters of 2-phenoxypropanoic acid was studied in detail. The ester of (R)-2-phenoxypropanoic acid and N-hydroxysuccinimide was found to be the most selective agent. The highest stereoselectivity was observed in the kinetic resolution of racemic 2-methylpiperidine in toluene at -40 °C (selectivity factor s = 73) with the predominant formation of (R,R)-amide (93.7% de). To explain the observed stereoselectivity, DFT modelling of the transition states in the reactions of the title acylating agent with 2-methylpiperidine and 2-methylpyrrolidine was performed. The calculated values were in good agreement with experimental data. It has been demonstrated that the acylation proceeds via a concerted mechanism, in which the addition of an amine occurs simultaneously with the elimination of the hydroxysuccinimide fragment. The high stereoselectivity of the (R,R)-amide formation is largely ensured by the lower steric hindrances in the transition states as compared to the formation of (R,S)-amide.
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Affiliation(s)
- Dmitry A Gruzdev
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Sergey A Vakarov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Marina A Korolyova
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Ekaterina V Bartashevich
- South Ural State University (National Research University), 76 Lenina Ave., Chelyabinsk 454080, Russia
| | - Andrey A Tumashov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Evgeny N Chulakov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Marina A Ezhikova
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Mikhail I Kodess
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Galina L Levit
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
| | - Victor P Krasnov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20 S. Kovalevskoy St, Ekaterinburg 620108, Russia.
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