Strongly Basic Reagents used in Organic Synthesis

Strongly Basic Reagents used in Organic Synthesis 

Alkali amides MNH2 are weaker bases than lithium dialkylamides. In this book their application as deprotonating agents is confined to a few cases cyclopropenes, for example, are easily deprotonated by potassium amide in liquid ammonia at low temperature [16]. 

1 Butyllithium was supplied by Chemetall GmbH, Frankfurt am Main, FRG, the European producer of lithium compounds, Grignard reagents, alcoxides, etc. 

For most syntheses sec- or /er/-butyllithium can be replaced by the very reactive combination of -butyllithium and potassium r-butoxide in THF [236, 239], This is a clear solution which can be prepared by mixing solutions of /-BuOK in THF and rz-BuLi in hexane at — 90 °C. The specific advantage of the BuLi /-BuOK-THF combination is the possibility of carrying out deprotonations that give thermo-labile metallic intermediates. Effectively, the reagent can be considered as an 

2 We are indebted to Dr. J.H. Wieringa for informing us about his experiences in preparing /-BuLi. 

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