Preparation of Stereodefined Secondary Alkyllithium Compounds |
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| Authors: | Stephanie Seel Dr Guillaume Dagousset Dr Tobias Thaler Annette Frischmuth Prof?Dr Konstantin Karaghiosoff Prof?Dr Hendrik Zipse Prof?Dr Paul Knochel |
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| Institution: | Department Chemie, Ludwig‐Maximilian‐Universit?t München, Butenandtstrasse 5–13, Haus F, 81377 München (Germany), Fax: (+49)?89218077680 |
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| Abstract: | We have developed a practical stereoretentive iodine/lithium‐exchange process that allows the stereodefined preparation of cis‐ and trans‐cycloalkyllithium compounds from their corresponding stereodefined iodides. Quenching with electrophiles offers stereospecific access to both cis‐ (up to 96 % cis) and trans‐cycloalkyl derivatives (up to 99 % trans). A detailed study of the thermodynamic stabilities, stereochemical behavior, and reactivities of axially and equatorially substituted cyclohexyllithium reagents is reported. Ab initio calculations demonstrate that the formation of oligomeric cyclohexyllithium structures is pivotal for explaining the observed stereochemical preference. |
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| Keywords: | diastereoselectivity lithiation solvent effects substituent effects synthetic methods |
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