Interception of Acyllithium

As described above, the most impressive progress in this field is the elegant (although acrobatic) trapping of acyllithium intermediates. In addition to Me SiCl [10], it has been shown that ketones [15, 16] and esters [15, 17] can be used as in situ trapping electrophiles (Eqs. (5.9) and (5.10)), and the amounts of the byproduct arising from the direct attack of RLi to the ketone can be decreased by using a lower reaction temperature of -135 °C and a smaller amount of the ketone 

Generally, the use of an aryllithium instead of an alkyllithium results in more complex reactions. These are illustrated in Eqs. (5.14) to (5.17) [23, 24]. 

Recently, Kabalka devised very interesting reactions in which the generated acyllithium is protonated by a pro-nucleophile to give an aldehyde, which then is attacked by the nucleophile formed (Eqs. (5.18) and (5.19)) [25, 26]. 

Kambe reported a useful entry to acyllithium using an efficient lithium-tellurium exchange reaction (Eq. (5.20)) [12]. 

Walton and Ricci found that an acylsilane underwent desilylation by a naked fluoride ion to give an acyl anion, which was then trapped in situ by an alkyl halide (Eq. (5.21)) [27]. 

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