Premium
ADDITION OF N ‐METHYLTRIAZOLINEDIONE TO BIADAMANTYLIDENE
Author(s) -
Nelsen Stephen F.,
Klein Susan J.
Publication year - 1997
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/(sici)1099-1395(199706)10:6<456::aid-poc908>3.0.co;2-j
Subject(s) - chemistry , adduct , reagent , benzene , hydrogen bond , reaction rate constant , chloroform , solvent , medicinal chemistry , computational chemistry , organic chemistry , molecule , kinetics , physics , quantum mechanics
The addition of N ‐methyltriazolinedione (M) to biadamantylidene (A) gives the [2+2] adduct P, but clearly does not proceed in one step beause an aminoaziridinium intermediate (I) can be observed to build up during the reaction. The overall rate of P formation correlates with the amount of I that builds up, but not with any solvent polarity parameter, despite the fact that charge‐separated intermediates are involved. NMR experiments established that the equilibrium constant for I formation is >1000 M −1 in CDCl 3 , ≥500 M −1 in CD 2 Cl 2 and in the range ca 2–15 M −1 for C 6 D 6 and C 6 D 5 Br. It is very unlikely that I is directly on the reaction pathway between M+A and P, and it is proposed that the zwitterionic intermediate with one CN bond, X, is the probable precursor of both I and P, although X does not build up in concentration enough to be observed. CH hydrogen bonding stabilizing both X and I in chloroform is suggested as a possible rationalization for the correlation between overall rate of P formation and stability of I relative to the starting materials. Formation of P in benzene is catalyzed by Meldrum's acid. M unfortunately reacts too rapidly with compounds containing OH bonds to study formation of P in the presence of strong hydrogen bonding reagents. © 1997 John Wiley & Sons, Ltd.