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Mechanistic insights into the autocatalyzed rearrangement of 2‐bromooxazolines to 2‐bromoisocyanates by means of high‐level quantum chemical methods
Author(s) -
Baroudi Abdulkader,
Karton Amir
Publication year - 2021
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.4214
Subject(s) - chemistry , bromide , quantum chemical , ion , reaction mechanism , molecule , computational chemistry , rearrangement reaction , mechanism (biology) , thermal , photochemistry , chemical physics , thermodynamics , inorganic chemistry , organic chemistry , catalysis , quantum mechanics , physics
A mechanism for the thermal instability and selective rearrangement of 2‐bromooxazolines is proposed and examined using the highly accurate G4(MP2) thermochemical protocol. We propose this rearrangement to be autocatalyzed by bromide ions that are initially formed via a bimolecular reaction between two 2‐bromooxazoline molecules. We find this step to be rate determining, and it results in a consequent and more favorable propagative reaction of bromide ions with the starting material (2‐bromooxazoline). The proposed mechanism sheds light on experimental observations and provides a coherent explanation for 2‐bromooxazolines thermal instability. We proceed to rationalize the high barrier of the rate‐determining step via comparison with experimentally known pathways.