Theoretical Study of the BF3-Promoted Rearrangement of Oxiranyl N-Methyliminodiacetic Acid Boronates
| Autor: | Silvina C. Pellegrinet, Margarita Vallejos |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Theoretical study oxiranyl N-methyliminodiacetic acid boronates 010405 organic chemistry Stereochemistry Otras Ciencias Químicas Organic Chemistry Ciencias Químicas Epoxide Carbocation 010402 general chemistry Ring (chemistry) 01 natural sciences Aldehyde 0104 chemical sciences chemistry.chemical_compound chemistry Density functional theory N-methyliminodiacetic acid BF3-promoted rearrangement CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | The Journal of Organic Chemistry. 82:5917-5925 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/acs.joc.7b01096 |
| Popis: | The mechanism of the rearrangement of oxiranyl N-methyliminodiacetyl (MIDA) boronates in dicholoromethane has been extensively investigated with density functional theory. Several reaction pathways were examined. Our results revealed that the most-favorable mechanisms for the BF3-promoted rearrangement of 2-phenyl oxiranyl MIDA boronate (1) and 1-phenyl oxiranyl MIDA boronate (24) comprise two steps: ring opening of the epoxide to a carbocation intermediate followed by migration of a MIDA-boryl group (for the reaction of 1) and hydrogen (for the reaction of 24), to give the same BF3-coordinated α-boryl aldehyde in both cases. The first step of the ring opening of the epoxide is the rate-determining step of these reactions. In the rearrangement step for the reaction of 1, the MIDA-boryl group migrates easily, probably because of its electron-rich sp3-hybridized boron center. For 24, the most-favorable pathway involves a rare boryl-substituted carbocation. The course of these reactions is mainly controlled by electronic effects, although steric effects are also significant. The higher energy barrier calculated for the unsubstituted oxiranyl MIDA boronate (31) explains the lack of reactivity in the studied BF3-promoted rearrangement. Fil: Vallejos, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; Argentina Fil: Pellegrinet, Silvina Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina |
| Databáze: | OpenAIRE |
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