Product configuration

Another transformation observed with a naturally occurring bacteriochlorin is the tautomer-ization of the exocyclic C — C double bond in bacleriochlorophyll b (3) in acetone which gives 7,8-dehydrobacteriochlorophyll a (4), a chlorin-type product (configurations at C7 and of the 8-ethylidene group have not been established).112,12... 

For reactions of A-acyliminium ions with alkenes and alkynes one has to distinguish between A-acyliminium ions locked in an s-trans conformation and those which (can) adopt an s-cis conformation. The former type reacts as a (nitrogen stabilized) carbocation with a C —C multiple bond. Although there are some exceptions, the intramolecular reaction of this type is regarded as an anti addition to the 7t-nucleophile, with (nearly) synchronous bond formation, the conformation of the transition state determining the product configuration. 

The problem of acquiring complete knowledge of candidate material grades should be resolved in cooperation with the raw material suppliers. It should be recognized that selection of the favorable materials is one of the basic elements in a successful product-configuration design, material selection, and conversion into a finished product (Appendix A PLASTICS DESIGN TOOLBOX). 

Solvent reorganization energy in the reactant and product configuration, respectively. Interaction energy in the ion-radical pair. 

The above methodology should enable control of product configuration by mere change in the reagent. Preparation of natural and unnatural amino acid... 

The above example illustrates the influence of the lattice on the constitution of the product. The photolysis of azobis-3-phenyl-3-pentane, 189, provides a case of influence on the product configuration (249). In this system, too, the crystal lattice favors disproportionation over combination. Two disproportionation products, the Z- and -pentenes 190 and 191, are formed in the solid, in a ratio of 1 3 the predicted equilibrium ratio is 1 1.6. While the nature of the processes determining this ratio is not clear, it was established that the Z isomer is formed under strong lattice control, whereas the E isomer is formed in a process with greater, but not complete, molecular freedom. 

R in starting compound 482 Reagent R Temperature CO Yield (%) e.e. (%) Product configuration... 

Scheme 6.97 Typical products obtained from the 91-catalyzed asymmetric allylation of N-benzoyl-protected aromatic hydrazones. The product configurations were not determined.

Fig. 8 Energy diagram for a general reaction that illustrates the formation of ground (yG) and excited (yE) state curves from the mixing of two configurations, cpR, the reactant configuration, and

Fig. 11 Energy diagram for a general reaction showing the formation of a ground state curve (yG) by the mixing of three configurations cpR, the reactant configuration, cpP, the product configuration, and , the intermediate configuration. Excited state curves are not shown...

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