The ethyl, 1- and 2-propyl, and other simple alkyl “carbanions” do not exist
✍ Scribed by Paul von Rague Schleyer; Günther H. Spitznagel; Jayaraman Chandrasekhar
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- French
- Weight
- 279 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Sumnary. A combination of experimental data and theoretical calculations has been used to estimate the electron affinities of simple primary, secondary, and tertiary alkyl radicals and the proton affinities of the corresponding anions. With the exception of cyclopropyl, such "carbanions" are indicated to be unstable towards loss of an electron and are not expected to exist as long-lived species in the gas phase. Although "carbanions" are the most widely used reactive intermediates in organic synthesis, they are the least well understood. Simple primary, secondary, and tertiary alkyl anions are as yet unknown as free entities. Their pK values in solution are only roughly estimated.2 Most of the species designated in oversimplified terms as "carbanions" are, in reality, polar organometallic derivatives (e.g., organolithium or Grignard reagents) which react as monomeric or aggregatated entities, rather than as free anions.3 CH3-is the only simple alkyl anion which has been observed in the gas phase.