Mears Kristian L, Stennett Cary R, Fettinger James C, Vasko Petra, Power Philip P
Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
Department of Chemistry, University of Helsinki, P.O. Box 55 (A. I. Virtasen aukio 1), 00014, Helsinki, Finland.
Angew Chem Int Ed Engl. 2022 May 23;61(22):e202201318. doi: 10.1002/anie.202201318. Epub 2022 Mar 30.
A series of alkali metal 1-adamantoxide (OAd ) complexes of formula [M(OAd )(HOAd ) ], where M=Li, Na or K, were synthesised by reduction of 1-adamantanol with excess of the alkali metal. The syntheses indicated that only one out of every three HOAd molecules was reduced. An X-ray diffraction study of the sodium derivative shows that the complex features two unreduced HOAd donors as well as the reduced alkoxide (OAd ), with the Ad fragments clustered together on the same side of the NaO plane, contrary to steric considerations. This is the first example of an alkali metal reduction of an alcohol that is inhibited from completion due to the formation of the [M(OAd )(HOAd ) ] complexes, stabilized by London dispersion effects. NMR spectroscopic studies revealed similar structures for the lithium and potassium derivatives. Computational analyses indicate that decisive London dispersion effects in the molecular structure are a consequence of the many C-H⋅⋅⋅H-C interactions between the OAd groups.
通过用过量碱金属还原1-金刚烷醇，合成了一系列通式为[M(OAd)(HOAd)]（其中M = Li、Na或K）的碱金属1-金刚烷氧基（OAd）配合物。合成表明，每三个HOAd分子中只有一个被还原。对钠衍生物的X射线衍射研究表明，该配合物具有两个未还原的HOAd供体以及还原的醇盐（OAd），Ad片段聚集在NaO平面的同一侧，这与空间位阻考虑相反。这是由于形成了通过伦敦色散效应稳定的[M(OAd)(HOAd)]配合物而导致醇的碱金属还原反应无法完全进行的首个例子。核磁共振光谱研究揭示了锂和钾衍生物具有相似的结构。计算分析表明，分子结构中决定性的伦敦色散效应是OAd基团之间许多C-H⋅⋅⋅H-C相互作用的结果。
