BEBOVIB program

Saunders, Shine and coworkers studied the kinetic isotope effects of the allyl vinyl ether and 2-OTMS allyl vinyl ether (Scheme 4.14) [15], The calculated KlEs using the BEBOVIB program gave results similar to those of Gajewski and Emrani, with 80% bond breaking for the C4-0 bond and 20% bond formation for the C1-C6 bond. 

Kupczyk-Subotkowska et al. studied heavy-atom kinetic isotope effects (KIE) of the thermal Claisen rearrangement of the parent [2- C]-, [4- C]-, [6- Cj- and [ 0]-allyl vinyl ether [38]. From the experimental KIEs they concluded, It is concerted a two-step process in which one bond is made (or broken) before the other is broken (or formed) is ruled out. From isotope effect calculations (BEBOVIB program) it was deduced that, "... the C4-O bond is 50-70% broken and the Cj-Cg bond 10-30% formed in the transition structure. ... 

These problems led Poirier et al.41 to re-investigate the relationship between the magnitude of the secondary a-deuterium KIE and transition state structure in SN2 reactions. The optimized geometries for the reactants and the transition structures for the Sn2 reactions where the nucleophile was F, Cl, OH, SH, NH2 or SCH3 and the substrate was either methyl fluoride or chloride were calculated at the HF/ 6-31+G level. Then, Sims BEBOVIB-IV program was used to carry out a... 

Model calculations of KIE for reactions 2 and 3 were carried out by use of the program BEBOVIB-IV (25) in the same manner as for reaction 1 (23). TS structures able to simulate the experimentally observed carbon and... 

Sims, L. B. Burton, G. W. Lewis, D. E. (1997). BEBOVIB-IV, QCPE No. 337. Quantum Chemistry Program Exchange, Department of Chemistry, University of Indiana, Bloomington, IN... 

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