| Abstract
| - A lithiation/electrophilic quench sequence involving a series of (η5-cyclohexadienyl)Mn(CO)3 complexes gives efficient access to a large panel of new derivatives. Theoretical investigations highlight the major role played by the Mn(CO)3 tripod on the regioselectivity of the reaction.
- An easy and versatile functionalization of (η5-cyclohexadienyl)Mn(CO)3 complexes by a lithiation/electrophilic quench sequence is described. Using TMSCl as a model electrophile, the reactivity of the series of substrates 1-5 was studied. In addition to the regiochemistry control by ortho-directing groups, such as OMe or Cl, the results suggest a strong influence of the Mn(CO)3 tripod conformation on the regioselectivity of the lithiation. In order to gain a better understanding of the reactivity features of the cyclohexadienyl ligand in the η5 complex, a theoretical investigation was undertaken. It indicates that the regioselectivity relies mainly on the intrinsic stabilities of the deprotonated intermediates, the species lithiated at C2, eclipsed by a Mn−CO bond, being the most stable one. The synthetic methodology was finally successfully extended to a representative range of electrophiles, giving access in good to excellent yields to η5 derivatives substituted by various heteroatoms (iodine, sulfur, or stannyl groups) or functions, such as ketone, ester, amide, or alcohols, α to the π system.
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