Department Chemie, Ludwig-Maximilian-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München, Germany.
Chemistry. 2013 Apr 2;19(14):4614-22. doi: 10.1002/chem.201204076. Epub 2013 Feb 10.
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.
我们开发了一种实用的立体保留碘/锂交换过程，允许从相应的立体确定的碘化物立体确定地制备顺式和反式环烷基锂化合物。用亲电试剂猝灭提供了对顺式（高达 96%顺式）和反式（高达 99%反式）两种环烷基衍生物的立体特异性进入。本文详细研究了轴向和赤道取代环己基锂试剂的热力学稳定性、立体化学行为和反应性。从头算计算表明，形成低聚环己基锂结构对于解释观察到的立体化学偏好至关重要。
