Diversity-oriented synthesis of analogues of the novel macrocyclic peptide FR-225497 through late stage functionalization

A concise synthetic approach to a class of biologically interesting cyclic tetrapeptides is reported which involves a late-stage functionalization of a macrocyclic scaffold through cross metathesis in an attempt to create diversity. The utility of this protocol is demonstrated through the preparation of three structural analogues of the important naturally occurring histone deacetylase inhibitor FR-225497.