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The desire for new synthetic methodologies for the rapid construction of enantiomerically pure substituted indole has been a fruitful driving force for chemical research in the last few years. This research line has produced a stunning array of enantioselective technologies either metal or organocatalyzed. This critical review documents the development of organocatalytic indole alkylation strategies, until the end of 2009 (127 references).

In recent years, organocatalysis has enhanced its importance as a tool for the synthesis of enantiomerically enriched compounds. Among the candidates for organocatalysis, the construction of asymmetric quaternary carbons is regarded as a challenging problem in organic synthesis. In particular, 3,3'-disubstituted oxindoles have one or more asymmetric quaternary carbon atoms and they represent a large family of bioactive compounds and synthetic derivatives that mimicry natural products. Therefore they are good targets for drug candidates and in the last two years many papers have appeared on organocatalytic methods for the synthesis of 3,3'-disubstituted oxindoles. Moreover, in the last few years 2-substituted and 2,2'-disubtituted 3-indolinones have also attracted the interest of chemists. This review aims to cover the literature on these topics from its origin to the end of 2011.

In 1989, the reaction of vinyl magnesium halides with ortho-substituted nitroarenes leading to indoles was discovered. This reaction is now frequently reported as the "Bartoli reaction" or the "Bartoli indole synthesis" (BIS). It has rapidly become the shortest and most flexible route to 7-substituted indoles, because the classical indole syntheses generally fail in their preparation. The flexibility of the Bartoli reaction is great as it can be extended to heteroaromatic nitro derivatives and can be run on solid support. This review will focus on the use of the Bartoli indole synthesis as the key step in preparations of complex indoles, which appeared in the literature in the last few years.

During the past four years, the research of new synthetic methodologies for the rapid construction of enantiomerically pure substituted indole has had a fruitful and important growth. This research line continues to produce stunning arrays of enantioselective technologies either metal or organocatalyzed. Thus, an update of our previous review (Chem. Soc. Rev., 2010, 39, 4449-4465) has become necessary and this critical review documents the literature on this topic, until the end of 2013.

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The introduction of magnetic nanoparticles (MNPs) has favoured the recovery of organocatalysts for asymmetric catalysis with techniques of magnetic separation.