A Combined Experimental−Theoretical Study on the Lithiation/Electrophilic Quench Sequence of (η5-Cyclohexadienyl)Mn(CO)3 Complexes

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• 作者：B&#xe9 ; atrice Jacques ; Alina Chanaewa ; Murielle Chavarot-Kerlidou ; Fran&#xe7 ; oise Rose-Munch ; Eric Rose ; H&#xe9 ; l&#xe8 ; ne G&#xe9 ; rard
• 刊名：Organometallics
• 出版年：2008
• 出版时间：February 25, 2008
• 年：2008
• 卷：27
• 期：4
• 页码：626 - 636
• 全文大小：710K
• 年卷期：v.27,no.4(February 25, 2008)
• ISSN：1520-6041

文摘

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.