Povarov cascade reaction

The Povarov cascade reaction of an aniline, two moles of formaldehyde and two moles of styrene gives tricyclic (51). ° Calix[4]- and calix[6]-arene sulfonic acids have been... 

A one-pot multicomponent cascade reaction of arylamines, aldehydes, and electron-deficient dienophiles on a soluble support under microwave conditions has been reported to involve a base-catalysed Povarov reaction and a [l,3]-sigmatropic rearrangement leading to 4,10-dihydropyrimido[l,2-fl]benzimidazoles (Scheme 17). ... 

In 2010, Wang et al. applied the gold(I)/chiral Brpnsted acid relay catalysis to a novel three-component cascade reaction, providing direct access to structurally diverse julolidine derivatives 374 in high optical purity (Scheme 2.99). The phosphoric acid (Se)-catalyzed asymmetric Povarov reaction of 2-(2-propynyl)anihnes 365, (V-vinylcarbamate 8, and aldehydes 3 provided enantioenriched tetrahydroquinoline intermediates 372, which then underwent a hydroamination reaction under the catalysis of a gold complex to give julolidine derivatives with up to >99% ee [133]. 

N. Shindoh, H. Tokuyama, Y. Takemoto, K. Takasu, J. Org. Chem. 2008,73, 7451-7456. Auto-tandem catalysis in the synthesis of substituted quinolines from aldimines and electron-rich olefins cascade Povarov-hydrogen-transfer reaction. 

Imino-Diels-Alder reaction [49] containing the coupling of imine and electron-rich alkene gradually became a powerful tool for the synthesis of quinazohne derivatives [50], In Povarov imino-Diels-Alder reaction, aniline and ethyl glyoxalate were chosen as substrates. And two molecules of a-iminoesters, which were obtained from the condensation of aniline and ethyl glyoxalate, were hypothesized to form the direct additive product. Cascade imino-Diels-Alder reaction conducted by Chenetal. [51] (Scheme 13.11) was extended from the Povarov imino-Diels-Alder reaction. In this research, researchers chose the same substrates as in the Povarov imino-Diels-Alder reaction, adopted various kinds of Lewis acids as catalysts, and finally produced quinazoline derivatives. Iron powder was determined as the optimized catalyst with highest yields. 

---