Synthetic Studies On The Immunosuppressive Agent-Fk-506 - Enantioselective Synthesis Of A C22-C34 Fragment

The C28C32 cyclohexyl group of the natural product, FK-506, was prepared enantioselectively from the iodolactone by replacement of iodide with retention of configuration. The C27C28 trisubstituted olefin was introduced stereoselectively via a classical aldol/elimination sequence employing titanium enolate methodology. Elaboration of this chemistry has led to a synthesis of a C22C34 fragment of the natural product.