Total synthesis of tricyclic azaspirane derivatives of tyrosine: FR901483 and TAN1251C

A solution to the long-standing problem presented by the oxidative cyclization of a phenolic 3-arylpropionamide to a spirolactam has been developed in this laboratory via oxazoline chemistry. This research was motivated by our interest in some novel tricyclic azaspirane natural products formally derived from tyrosine, such as FR901483 and TAN1251C. In this paper, we disclose full details of the total synthesis of these substances.