Krzysztof Staliński

Oxidative nucleophilic substitution of hydrogen in nitroarenes with phenylacetonitrile derivatives

Abstract Tertiary carbanions generated from α-substituted phenylacetonitriles in liquid ammonia add to nitro-benzenes in the para position to form the corresponding σH-adducts which are transformed, depending on the starting nitriles and the reaction conditions, to products of oxidative nucleophilic substitution of hydrogen, ONSH or vicarious nucleophilic substitution, VNS.

ISOTOPE EFFECT IN OXIDATIVE NUCLEOPHILIC SUBSTITUTION OF HYDROGEN IN NITROARENES

Abstract In a series of competitive experiments with labelled nitrobenzenes carried out in liquid ammonia at −70 °C it was shown that the rate of oxidative substitution of hydrogen with the carbanion of 2-phenylpropionitrile is ca . 9.8 times faster than the analogous substitution of deuterium in 4-D-nitrobenzene and perdeuterionitrobenzene. Thus C arom. -H bond breaking is the rate limiting step of the oxidative process.

Oxidative nucleophilic substitution of hydrogen in nitrobenzene with 2-phenylpropionitrile carbanion and potassium permanganate oxidant

The carbanion of 2-phenylpropionitrile adds to nitrobenzene in the p-position in liquid ammonia to give the relative stable σH-adduct which is oxidised with KMnO4 to 2-phenyl-2-(4-nitrophenyl)propionitrile; the relationships of rates of various reactions in these systems are estimated.

Application of the Radical Cascade of Acyclic Peptide-Based Precursors into Analogues of Type I β-Turn

Radical cyclizations of di-, tri- and tetrapeptides containing N-2-bromobenzyl,N-methyl-substituted alanine or aspartic acid lead in good yields to α,β-unsaturated γ-lactams. The overall cascade, relying on a hydrogen atom transfer-elimination strategy could serve as a way to incorporate a flat and rigid five-membered ring into the peptide framework.