Total Synthesis of Ovafolinins A and B: Unique Polycyclic Benzoxepin Lignans through a Cascade Cyclization
David Barker describes the formation of polycyclic benzoxepin lignans through a cascade cyclization.
Since 2009, the research group of Professor David Barker at the University of Auckland (New Zealand) has been interested in the use of the acyl-Claisen rearrangement and its application to the synthesis of lignan natural products. They have previously used this approach to synthesize different lignan subclasses including tetrahydrofuran lignans, diarylbutanol lignans and aryl tetralin lignans. He claimed that “ovafolinins A and B represent unique structural targets as they are the only examples of lignan natural products containing a seven-membered benzoxepin penta- or tetracyclic scaffold, respectively.” This allowed the group to determine the power and utility of their approach to complex natural products.