Structural Revision of Cephalosporolide J and Bassianolone

The NMR spectra for three “natural”
products: cephalosporolide
C (Ces-C), cephalosporolide J (Ces-J), and bassianolone were found
to be identical, and we proposed that Ces-C was the correct structure
for the reported spectra. The first total synthesis of the proposed
structure for Ces-J was achieved to support our structural revision
for Ces-J. Chemical transformations of bassianolone and computational
prediction of 13C NMR spectra allowed us to conclude that
Ces-C was the correct structure for bassianolone. Our synthetic and
computational studies suggested that these “different”
natural products Ces-C, Ces-J, and bassianolone have the same structure:
Ces-C.