Flavonoids are privileged structural motifs in numerous natural products and
pharmaceutical molecules, which show many biological activities such as antitumor,
antioxidant, antibacterial and anti-inflammatory properties. Flavanone and chromanone
which feature a chiral center are subgroups of flavonoids. The structures of flavanone
and chromanone are distinct from that of flavone and chromone by a reduction of C2-
C3 double bond. Deoxygenation of flavanones and chromanones provides chromenes
which are also important structural motifs present in a number of natural and synthetic
products that exhibit a wide range of biological activities. Besides naturally occurring
flavanones, chromanone, and chromenes, the benzopyran scaffold is an important
intermediate and interesting building block in organic synthesis and design of new lead
compounds in drug discovery. Consequently, many attention has been paid to their
efficient synthesis, especially in enantiopure forms, and many asymmetric methods for
the construction of the chiral flavanone, chromanone and chromene skeletons were
reported in recent years.
Keywords: Allylic Cyclization, Asymmetric Synthesis, Chromanone, Chromene,
Conjugate Addition, Flavanone, Flavonoid, Reduction.
