A molecular electron density theory (MEDT) study for the [3 + 2] cycloaddition (32CA) reaction of indoledione and N-methyl glycine with (E)-1-bromonitrostyrene leading to the spirooxindole-pyrrolidine adduct is presented. Electron localisation function (ELF) study of the in situ generated azomethine ylide classifies a pseudodiradical electronic structure associated with low activation energies. This 32CA reaction is a polar process with electronic flux from the strongly nucleophilic azomethine ylide to the strongly electrophilic nitrostyrene, confirmed from the global electron density transfer (GEDT) above 0.20 e at the transition states (TSs). Parr function analysis predicts the correct regioselectivity from the two-centre interactions. The reaction is kinetically controlled with negative free energy of reaction which makes it irreversible. The activation enthalpy of the favoured TS is lowered by 3.4, 6.3 and 9.3 kcal mol −1 in methanol relative to the other feasible reaction paths,
Diastereoselective [3 + 2]-cycloadditions of oxindoles with α,β-disubstituted nitroethylenes: regioreversed spiropyrrolidines show potent MRSA activity.
Diastereoselective reactions supported by metals and nonmetals offer a multifaceted path for the synthesis of robust intermediates of value to academia and industry. The reactions that involve mono‐ and disubstituted electron‐rich and electron‐deficient olefins offer facile construction of stereogenic carbon centers. Recent advances in the development of methods and an understanding of the chemistry of oxindoles has led to approaches that provide high levels of facial control, regiocontrol and diastereoselectivity. Part I of this focus review is devoted to the chemistry of β‐monosubstituted alkylidene oxindoles. Herein, we discuss reports made over the last decade of diastereoselective reactions that involve oxindole‐containing trisubstituted alkenes, which lead to the generation of stereogenic centers and the formation carbocyclic and heterocyclic skeletons.
Part II encompasses synthetic efforts towards the construction of acyclic and cyclic structures that contain carbon and heteroatoms by employing diastereoselective reactions of β,β′‐disubstituted alkylidene oxindole as the primary substrate. In addition to the construction of acyclic structures, carbocyclic and heterocyclic rings that contain three‐, five‐, six‐, and seven‐membered spirocycles or fused‐rings are also described. A few examples of the arylative cyclization of dienes have also been presented.
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