Josue S. Bello Forero, Joel Jones Junior and Flavia M. da Silva Pages 157 - 175 ( 19 )
Tetrahydroquinoline (THQ) subunits are present in many natural products and biologically active agents, such as anti-viral, anti-biotic, and anti-tumour medications. The synthesis of THQs is described extensively in literature due to the search for a general, simple, efficient and low-cost preparation method. The retrosynthetic analysis for THQ synthesis has many strategies involving the formation of one or two C-C or C-N bonds. In 1963, Povarov et al. published two studies named “A new type of diene condensation reaction” and “Reaction of benzylideneaniline with some unsaturated compounds". These studies described a converging reaction for the formation of two C-C bonds. However, in addition to using easily available starting material, this route remained unexplored for thirty-two years as the result of a small product yield, the need of previous formation of the precursor imines, and the use of stoichiometric amounts of the catalyst. However, in 1995, Kobayashi et al. performed the one-pot multi-component version of the Povarov reaction among anilines, aldehydes and alkenes acting as dienophiles, and this reaction was catalysed by Lewis acids and resulted in reasonable yields. Thus, the Povarov reaction was reborn to researchers. Currently, the Povarov reaction is classified into three wellstudied categories as follows: i) the original one-pot ABC using aniline, aldehydes and activated alkenes; ii) the ACC' using anilines and two equivalents of dienophile; and iii) AA'BB' involving the use of two equivalents of aniline and two equivalents of enolisable aldehyde.
Cycloaddition, Dienophile, Heterocycles, Imines, Lewis acid, Povarov Reaction, Tetrahydroquinoline.
Sintese Organica Ambiental SOA - Dept. Quimica Organica - Instituto de Quimica - UFRJ - CP 68.584, 21941-972, Rio de Janeiro, RJ, Brazil.