Background:
The majority of naturally occurring compounds, pharmaceuticals, and drug-candidate
molecules possess heterocyclic scaffolds. In this context, tetrahydobenzo[b]pyrans are of considerable importance.
In the line with the synthesis of these valuable heterocyclic compounds, the researchers tried to synthesize
these molecules using different organocatalysts. The development of new strategies for three-component
condensation of dimedone, various aldehydes and malononitrile for construction of tetrahydrobenzo[b]pyrans
is of particular interest to organic chemists and pharmacologists.
Objective:
In this review, three-component catalyzed synthesis of tetrahydrobenzo[b]pyran compounds is
introduced, focusing on the developments in the use of organocatalysts. Organocatalytic approaches were
investigated for the synthesis of tetrahydrobenzo[b]pyrans. This contribution covers the literature concerning
the synthesis of heterocycles referred to, in recent times.
Conclusion:
This review article is associated with the study of the three-component synthesis of
tetrahydrobenzo[b]pyrans using organocatalysts. This review also provides an insight into the importance of
these heterocycles. In the vast majority of these reactions, water and water-ethanol system have been used as
green solvent media for implementation of them. The use of green solvents, the development of less toxic and
promising reagents/catalysts as well as the design of inexpensive and reliable approaches are some of the principles
of green chemistry, and most of the methods are benefited from them. Tetrahydrobenzo[b]pyrans and
organocatalysts open avenue ofnew horizons. The recyclability of the many of these organocatalysts offers an
additional merit for the use of these catalysts in 3-CR of aldehydes, dimedone, and malononitrile reactions.
Lactic acid as an invaluable green solvent for ultrasound-assisted scalable synthesis of pyrrole derivatives
