One‐Pot Synthesis of Enantioenriched β‐Amino Secondary Amides via an Enantioselective [4+2] Cycloaddition Reaction of Vinyl Azides with N ‐Acyl Imines Catalyzed by a Chiral Brønsted Acid
| Autor: | Jun Kikuchi, Masahiro Terada, Atsushi Kaga, Taishi Nakanishi, Shunsuke Chiba |
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| Rok vydání: | 2020 |
| Předmět: |
010405 organic chemistry
Organic Chemistry One-pot synthesis Enantioselective synthesis General Chemistry 010402 general chemistry 01 natural sciences Medicinal chemistry Catalysis Cycloaddition 0104 chemical sciences chemistry.chemical_compound chemistry Nucleophile Acid hydrolysis Nitrilium Brønsted–Lowry acid–base theory |
| Zdroj: | Chemistry – A European Journal. 26:8230-8234 |
| ISSN: | 1521-3765 0947-6539 |
| DOI: | 10.1002/chem.202002049 |
| Popis: | A catalytic enantioselective synthesis of β-amino secondary amides was achieved using vinyl azides as the enamine-type nucleophile and chiral N-Tf phosphoramide as the chiral Brønsted acid catalyst through a five-step sequential transformation in one pot. The established sequential transformation involves an enantioselective [4+2] cycloaddition reaction of vinyl azides with N-acyl imines as the key stereo-determining step that is efficiently accelerated by a chiral N-Tf phosphoramide catalyst in a highly enantioselective manner in most cases. Further generation of the iminodiazonium ion intermediate through ring opening of the cycloaddition product and subsequent skeletal rearrangement involving Schmidt-type 1,2-aryl group migration followed by recyclization of the resulting nitrilium ion were also initiated by the same acid catalyst. Final acid hydrolysis of the recyclized products in the same pot gave rise to enantioenriched β-amino amides through C-C bond formation at the α-position of the secondary amides. |
| Databáze: | OpenAIRE |
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