Asymmetric reduction of CC and CO bonds: stereochemical approach

Павлов, В. А.; Клабуновский, Е. И.; Struchkov, Yu. T.; Voloboev, A. A.; Yanovsky, A. I.

doi:10.1016/0304-5102(88)80034-8

Cited by 56 publications

(10 citation statements)

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“…The available data also reveal that the mechanistic statements regarding temperature-dependent selectivity by Halpern et al [167- [176] on the other may be valid for many systems in a particular temperature region, but they cannot explain simply a changed or inverse temperature dependence in another temperature range. Temperature does not have an isolated effect in one catalytic step, but in the dynamic model of the isoinversion relationship according to Scheme 3 it can lead to a reweighting of the enthalpy/entropy dominance in selectivity-determining partial steps.…”

Section: The Influence Of Temperaturementioning

confidence: 93%

The Isoinversion Principle—a General Model of Chemical Selectivity

Buschmann¹,

Scharf²,

Hoffmann³

et al. 1991

Angew. Chem. Int. Ed. Engl.

351

138

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Dedicated to Vladimir Prelog and to the memory of Horst PracejusA large number of successful methods for chirality transfer, using either stoichiometric or catalytic chiral auxiliaries, are in use today. However, there is a lack of practical and dynamic selectivity models, i.e. models which take into account the entire reaction sequence, and which allow simple and reliable assessment, optimization and prediction of selectivity in asymmetric syntheses. The models that are available are either too strongly biased to the steric requirement of the particular molecules reacting, but do not go beyond classical considerations of static facial differentiation, or they take a demanding, theoretical approach, which because of its inherent limitations and the great theoretical effort required has not yet found its way into the practical world of the synthetic chemist. The "Isoinversion Principle", developed on the basis of Eyring's theory, closes this gap. With its aid, the synthetic chemist can determine the characteristic isoinversion temperature for the reaction type of interest from a few temperature-dependent measurements of selectivity parameters. then affords information on interesting questions such as optimization etc. The advantage of this method is that it is useful not only for stereoselectivity, but for any kind of process where selectivity in general (regio-, chemo-, etc) is generated at two or more stages of a reaction sequence, regardless of whether these reactions involve the ground state or a diabatic photoprocess. The present review will demonstrate that this generation of selectivity at two or more stages of a reaction sequence occurs more commonly than is generally thought.

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Section: The Influence Of Temperaturementioning

confidence: 93%

The Isoinversion Principle—a General Model of Chemical Selectivity

Buschmann¹,

Scharf²,

Hoffmann³

et al. 1991

Angew. Chem. Int. Ed. Engl.

351

138

View full text Add to dashboard Cite

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“…35 The proposed explanation is also confirmed by the fact that rhodium hydride was observed in the reaction mixture at low temperature (720 8C). 37 Upon hydrogenation of the enamide substrate on complexes with bppm and PheNOP, asymmetric induction occurs during the transformation of an asymmetric intermediate.…”

Section: Asymmetric Induction In the Stage Of Substrate Coordination ...mentioning

confidence: 99%

Mechanisms of asymmetric induction in catalytic hydrogenation, hydrosilylation and cross-coupling on metal complexes

Павлов¹

2002

Russ. Chem. Rev.

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The positive frequency dependent polarizability of atoms a(w) is discussed in terms of the particle-hole polarization propagator. It is considered in the simplest approximation defined by the Bethesalpeter equation which includes a subset of particle-hole interactions to all orders in the Coulomb potential. Its solution is used to show that when the polarizability is formulated in terms of an effective dipole matrix element of the atomic sub-shells, the interaction kernel is symmetric and hence makes the central quantity in the formulation, the polarization function, hermitian.

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“…This model was further extended to rhodium complexes used for enamide hydrogenation with seven-membered chelate rings in the l-twist-chair and d-twist-chair conformations. 10, 52 ± 56 Similar dependences were found for hydrosilylation, 10,55 cross-coupling 10,57,58 and allylic alkylation 59 on Rh, Ni, Pd, etc. complexes.…”

Section: Configurational Models In Asymmetric Homogeneous Catalysismentioning

confidence: 54%