Synthesis of Putative Uniflorine A

A diastereoselective synthesis of the putative structure of the natural product uniflorine A has
been achieved by using the Petasis borono−Mannich reaction and ring-closing metathesis as key
steps. The NMR data of the synthetic material did not match that reported for the natural product.
The structure of the final synthetic product was unequivocally determined by single-crystal X-ray
study of its pentaacetate derivative. Thus it was concluded that the proposed structure of uniflorine
A is incorrect.