Adams catalyst substitution reactions

Adams catalyst (Pt02/H+) reductions of the substituted benzoic acids are generally rapid but usually give product ratios characteristic of kinetic controlled reactions. Reductions in strong base with Raney nickel catalyst appear to give the equilibrated (thermodynamic) product. 

Compared to metal-catalyzed asymmetric epoxidation reactions, asymmetric versions of this reaction without the need of a catalyst (apart from a base) are rarely known. In 2000 Adam and coworkers reported a method for the asymmetric Weitz-Scheffer epoxidation of substituted enones 91 by the secondary, optically active hydroperoxide (5 )-(l-phenyl)ethyl hydroperoxide (equation 27, Table 10). ... 

All classes of vicinal diols (primary, secondary, tertiary, alkyl- or aryl-substituted) will undergo the pinacol rearrangement, and many acids and solvents have been used for this purpose. Various procedural modifications have been introduced over the years for particular glycols, but sulfuric acid remains the most commonly employed catalyst. The use of 25% H2SO4, as recommended in the procedure of Adams, affords pinacolone in essentially quantitative yield. In some instances better results are obtained when cold concentrated acid is used as the solvent. The choice of reagents and conditions is important, and can completely alter the course of the reaction. For example, pinacol also serves as the starting material for the synthesis of 2,3-dimethylbutadiene, formed by slow distillation of a mixture of the diol and catalytic HBr. ... 

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