Premium
Unraveling the Mechanism of the Ir III ‐Catalyzed Regiospecific Synthesis of α‐Chlorocarbonyl Compounds from Allylic Alcohols
Author(s) -
Li Man,
SanzMarco Amparo,
MartinezErro Samuel,
GarcíaVázquez Víctor,
Mai Binh Khanh,
FernándezGallardo Jacob,
Himo Fahmi,
MartínMatute Belén
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002845
Subject(s) - isomerization , allylic rearrangement , tautomer , chemistry , protonation , catalysis , ketone , catalytic cycle , medicinal chemistry , yield (engineering) , hydride , reaction mechanism , kinetic isotope effect , photochemistry , alcohol , computational chemistry , organic chemistry , deuterium , hydrogen , ion , physics , quantum mechanics , materials science , metallurgy
We have used experimental studies and DFT calculations to investigate the Ir III ‐catalyzed isomerization of allylic alcohols into carbonyl compounds, and the regiospecific isomerization–chlorination of allylic alcohols into α‐chlorinated carbonyl compounds. The mechanism involves a hydride elimination followed by a migratory insertion step that may take place at Cβ but also at Cα with a small energy‐barrier difference of 1.8 kcal mol −1 . After a protonation step, calculations show that the final tautomerization can take place both at the Ir center and outside the catalytic cycle. For the isomerization–chlorination reaction, calculations show that the chlorination step takes place outside the cycle with an energy barrier much lower than that for the tautomerization to yield the saturated ketone. All the energies in the proposed mechanism are plausible, and the cycle accounts for the experimental observations.