Combining Neopentyllithium with Potassium tert-Butoxide: Formation of an Alkane-Soluble Lochmann-Schlosser Superbase
Combining Neopentyllithium with Potassium tert-Butoxide: Formation of an Alkane-Soluble Lochmann-Schlosser Superbase
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DOI：
10.1002/anie.201602792
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发表时间：
2016-08-26
影响因子：
16.6
通讯作者：
Klett, Jan
中科院分区：
文献类型：
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作者：
Benrath, Philipp;Kaiser, Maximilian;Klett, Jan
烷基锂和较重的碱金属醇盐的混合物通常用于形成较重的碱金属的烷基化合物，但是这些混合物还已知它们在去质子化金属化反应中的高反应性。这些有机金属混合物通常被称为LiC-KOR超强碱，但尽管有许多努力，它们的组成仍然未知。本文中，我们提出了通过新戊基锂与叔丁醇钾反应制备的混合碱金属烷基/烷氧基化合物。成功的关键是新戊基碱金属化合物具有良好的溶解性和温度稳定性，导致己烷可溶的混合物，允许在环境温度下处理和通过结晶分离。固态和溶液中的化合物通过X-射线晶体学和NMR光谱鉴定为不同组成的锂/钾新戊基/叔丁氧基聚集体LixKyNpz（OtBu）（x+y-z）的混合物。
Mixtures of alkyllithium and heavier alkali-metal alkoxides are often used to form alkyl compounds of heavier alkali metals, but these mixtures are also known for their high reactivity in deprotonative metalation reactions. These organometallic mixtures are often called LiC-KOR superbases, but despite many efforts their constitution remains unknown. Herein we present mixed alkali-metal alkyl/alkoxy compounds produced by reaction of neopentyllithium with potassium tert-butoxide. The key to success was the good solubility and temperature-stability of neopentyl alkali-metal compounds, leading to hexane-soluble mixtures, which allowed handling at ambient temperatures and isolation by crystallization. The compounds in solid state and in solution were identified by X-ray crystallography and NMR spectroscopy as mixtures of lithium/potassium neopentyl/tert-butoxy aggregates of varying compositions LixKyNpz(OtBu)(x+y-z).