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Theoretical studies on the reactions of substituted phenolate anions with formate esters
Author(s) -
Park Young Sook,
Kim Chang Kon,
Lee BonSu,
Lee Ikchoon,
Lim Woong Mook,
Kim Wang Ki
Publication year - 1995
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610080502
Subject(s) - chemistry , formate , solvation , nucleophile , proton affinity , concerted reaction , medicinal chemistry , ion , transition state , proton , photochemistry , computational chemistry , inorganic chemistry , organic chemistry , catalysis , physics , protonation , quantum mechanics
Semiempirical MO (PM3) studies are reported on the reactions of 18 substituted phenolate anions with m ‐(MNPF), p ‐(PNPF) and 3,4‐dinitrophenyl formates (DNPF). The mechanistic change from rate‐limiting formation to breakdown of the anionic intermediate (T − ) can occur in the gas phase, especially for MNPF, at approximately an equal proton affinity ( PA ) of the nucleophile and leaving group phenolates, i.e. Δ PA = 0 as the PA of the phenolate anion is decreased. In solution, however, owing to the low stability of T and a greater stabilization by solvation of the transition state for the breakdown step (TS2), all three formate esters are predicted to proceed by a concerted mechanism, which is in agreement with the experimental results. The low stability of T can be ascribed to the relatively high electron affinity of the phenolate anions.