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Theoretical investigation of the abnormal Reimer–Tiemann reaction
Author(s) -
Castillo R.,
Moliner V.,
Andrés J.,
Oliva M.,
Safont V. S.,
Bohm S.
Publication year - 1998
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/(sici)1099-1395(199808/09)11:8/9<670::aid-poc56>3.0.co;2-u
Subject(s) - chemistry , polarizable continuum model , dimethyl ether , computational chemistry , pyrrole , density functional theory , ring (chemistry) , transition state , molecular geometry , potential energy , solvent effects , solvent , molecule , organic chemistry , atomic physics , physics , methanol , catalysis
The molecular mechanism for the pyrrole ring expansion to yield 3‐chloropyridine, as a model of the abnormal Reimer–Tiemann rearrangement, was characterized theoretically in vacuo by means of the HF/6–31G* computational method. The electron correlation was estimated at the MP2/6–31G* level and by calculations based on density functional theory, B3LYP/6– 31G* and B3LYP/6– 31+G*. Solvent effects of the diethyl ether and ethanol media were analyzed by using a polarizable continuum model. The stationary points were characterized with analytical gradient techniques in the gas phase and insolvents. The topology of the potential energy surfaces calculated at the MP2/6–31G* and B3LYP/6–31G* levels shows that the molecular mechanism corresponds to an inverted energy profile along one intermediate, associated with the addition of dichlorocarbene at the β‐position of the pyrrole anion, and only one transition structure related to the ring expansion associated with the breaking and forming of Cα—Cβ and C—Cα bonds, respectively, and the Cl − leaving process. © 1998 John Wiley & Sons, Ltd.