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AB initio calculations of Diels–Alder transition structures for hetero‐dienophile additions to cyclopentadiene
Author(s) -
Jursic Branko S.,
Zdravkovski Zoran
Publication year - 1994
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.610071109
Subject(s) - cyclopentadiene , chemistry , ab initio , computational chemistry , diels–alder reaction , ab initio quantum chemistry methods , transition state , alder , organic chemistry , molecule , catalysis , botany , biology
Transition states for the hetero‐Diels–Alder addition of formaldehyde, formaldimine, diazene and nitrosyl hydride to cyclopentadiene were located with ab initio molecular orbital calculations. Asynchronous transition structures were located for the asymmetric hetero‐dienophiles, whereas the symmetrical hetero‐dienophile, cis ‐diazene, produced a synchronous transition structure. The relative reactivities are in good agreement with the LUMO energies of the hetero‐dienophiles, and the transition states with the exo oxygen or nitrogen lone pairs have lower energies than the corresponding endo lone electron pair transition states. Endo / exo energy differences are much higher than in the addition of ethylene derivatives to cyclopentadiene.