Using perturbation and frontier molecular orbital theory to predict diastereofacial selectivity

Article Abstract:

The preferred side of attack of unsymmetrical molecules, such as substituted ketones, which leads to diastereofacial selectivity, can be predicted using electronic analytical methods. However, studies on this predictive ability reveal that there are only very small differences involved in the activation energies leading to the observed selectivities. Also, there are a myriad of possible interactions that might contribute to these differences. A potential workable approach makes use of orbital energies and elaborations resulting from molecular orbital calculations on the reactive substrates.

Usage, Ketones, Molecular orbitals, Perturbation (Quantum dynamics), Perturbation (Mathematics)

---

Structure distortions in heteroatom-substituted cyclohexanones, adamantanones, and adamantanes: origin of diastereofacial selectivity

Article Abstract:

Two pyramidal structures have been calculated for the ammonia complex of 5-boraadamantyl radical. The radical's symmetry is due to the absence of heteroatom substitution. Once a heteroatom substitutes for a carbon atom, the resulting cage structure is no longer symmetrical at the carbonyl group. The calculated energy difference between the cis radical and the trans radical correlates with the observed selectivity in the radical substitution of 5-bora-2-adamantyl chloride. Thus, the observed deastereofacial selectivity is accountable by structure distortion.

Structure-activity relationships (Biochemistry), Carbonyl compounds, Ammonium compounds, Ammonium salts

---

Nature of the electronic factor governing diastereofacial selectivity in some reactions of rigid saturated model substrates

Article Abstract:

The nature of the electronic factor governing stereofacial selectivity in reactions of 5-substituted (X) 2-adamantyl derivatives requires consideration of both electrostatic and hyperconjugative effects. Either effect or both may be important depending on electron demand at the reaction center as well as the electronic character of the substituent. Findings indicate that hyperconjugation is the dominant factor for sigma-electron donor groups which usually have negligible polar field influences.

Electrostatics, Electrochemistry, Electron donor-acceptor complexes

Similar abstracts:

• Abstracts: Chiroptical molecular switches. Three-dimensional optical data storage using photochromic materials
• Abstracts: Charge carrier transporting molecular materials and their applications in devices. Development of dendrimers: Macromolecules for use in organic light-emitting diodes and solar cells
• Abstracts: Selective preparation of complex polycyclic molecules from acyclic precursors via radical mediated- or transition metal-catalyzed cascade reactions
• Abstracts: Kinetics of thermal racemization of (2S,3S)-1-13C-1,2,3-d3-cyclopropane followed by vibrational circular dichroism spectroscopy
• Abstracts: Electrochemical study of the pore structure of sandstone and similar media

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.