A full account of the total synthesis of (±)-cassumunins A–C – superior antioxidants
and anti-inflammatory agents – is given. Two novel approaches were developed for synthesizing
cassumunins. The total synthesis of cassumunins A and B was accomplished in five linear
steps from a known aldehyde in good overall yields of 50 and 43%, respectively, featuring
a cascade [3,3]-sigmatropic shift (the Claisen rearrangement) and Heck cross-coupling
reaction. Consequently, the total synthesis of cassumunin C was accomplished in three
linear steps from a known alcohol with an overall yield of 53%. The key features involved
in this synthesis are tandem [3,3]-sigmatropic shift, SN2′ reaction, and aldol condensation. Moreover, a total of eighteen symmetrical and
unsymmetrical curcumin analogues were synthesized.
Key words
total synthesis - Claisen rearrangement - S
N2′ reaction - cassumunins A–C - curcumin - Heck reaction - aldol condensation