Ab initio transition structures for hydroborations of alkenes, allenes, and alkynes by borane, diborane, methylborane, methylfluoroborane, and dimethylborane

Tri-n-Butylborane/WaterComplex-Mediated Copolymerization of Methyl Methacrylate with Proteinaceous Materials and Proteins: A Review

“…The weight of MMA-homopolymer formed, the molecular weight, and the number of polymers formed for the polypeptides as a whole were (1.1-1. Currently, computational chemistry has being applied for analyzing the transition structures for the hydroboration of alkenes by borane compounds at the semi-empirical MO calculation level and DFT levels [26][27][28]. It has been reported previously that the relative rates of hydroboration of alkenes are well correlated with their semi-empirical MNDO-calculated HOMO energy level.…”

“…This can be accounted for by the enhanced interaction between the HOMO of alkenes and the LUMO of boranes when they are brought together. Formation of the B-C bond occurs predominantly at the position where the atom orbital coefficient in the alkene HOMO is largest [26,27]. To explain the present co-catalytic effect of amino acids and the graft copolymerization with polypeptides, the HOMO-LUMO interaction provides a deeper understanding of tri-n-butylborane-initiated polymerization and copolymerization chemistry.…”

“…Consideration of the interaction of HOMO of alkenes and LUMO of boranes [26,27] could be applied for study of polypeptides. The relationship between the number of grafted-PMMA branches of polypeptides and the Δε HOMO of corresponding amino acids has been examined.…”

Hydroboration of Cyclopropane: A Transition State Study

“…Ab initio molecular orbital study of the hydroboration of ethylene with borane (BH 3 ) showed that reaction proceeds through the formation of three-centered intermediate complex followed by the formation of four-centered transition state. In 1990, Wang et al 3 have extensively carried out the hydroboration of alkenes, allenes and alkynes and showed that the formation of triangular π-complex which then deform into the addition product via four-centered transition state. Seyferth 4 and Streitwieser 5 on the stereochemical ground predicted the threecentered transition state.…”

Hydroalumination of Cyclopropane: A Transition State Study

“…Qualitatively, the energetics of these pathways compare well with those from the simple hydroalumination reaction studied earlier. Schleyer and Hommes 26 have examined the structure of the transition state for the reaction of dimethylborane and ethylene using correlated methods and suggest that the TS has a three-centered rather than fourcentered structure. Chey et al 27 have previously characterized the π-complex intermediates for hydroalumination of alkenes.…”