Total synthesis of fomitellic acid B

Herein, we describe the first total synthesis of fomitellic acid B (2), a potent inhibitor of DNA polymerases alpha and beta. There are two key features in this synthesis: (i) the AB ring system, with all requisite chiral centers, is stereoselectively constructed by means of titanium(III)-mediated radical cascade cyclization of epoxypolyene; and (ii) an enone moiety in the B-ring is generated by isomerization of an olefin followed by allylic oxidation. (C) 2009 Elsevier Ltd. All rights reserved.