Methyl Cation Affinities of Canonical Organic Functional Groups

Methyl cation affinities are calculated for the canonical nucleophilic functional groups in organic chemistry. These methyl cation affinities, calculated with a solvation model (MCA*), give an emprical correlation with the Ns(N) term from the Mayr equation under aprotic conditions when they are scaled to the Mayr reference cation (4-MeOC6H4)(2)CH+ (Mayr E = 0). Highly reactive anionic nucleophiles were found to give a separate correlation, while some ylides and phosphorus compounds were determined to give a poor correlation. MCA*s are estimated for a broad range of simple molecules representing the canonical functional groups in organic chemistry. On the basis of a linear correlation, we estimate the range of nucleophilicities of organic functional groups, ranging from a C-C bond to a hypothetical tert-butyl carbanion, toward the reference electrophile to be about 50 orders of magnitude.

Automated summary

The methyl cation affinities of canonical nucleophilic functional groups in organic chemistry were calculated, revealing empirical correlations when scaled to a reference cation. Different reactivity levels of anionic nucleophiles showed separate correlations, while ylides and phosphorus compounds exhibited poor correlations. The nucleophilicity range of organic functional groups was estimated to be about 50 orders of magnitude based on a linear correlation analysis.