A Second Generation Synthesis of Roseophilin and Chromophore Analogues

A concise, flexible, and high-yielding synthesis of the macrocyclic compound 4 is outlined which served as a key intermediate in a previous total synthesis of the antitumor active alkaloid roseophilin 1 . The key steps of this approach consist of a Pd(0)-catalyzed reaction of vinyloxirane 6 with sulfone 7 and in a subsequent ring closing metathesis (RCM) reaction for the formation of the 13-membered ring catalyzed by the ruthenium carbene Cl 2 (PCy 3 ) 2 Ru CHCH CPh 2 introduced by Grubbs. Moreover, nitrile ylide cycloaddition reactions are used for the preparation of roseophilin side chain mimics. Finally, the synthesis of various chromophore analogues of 1 is reported, including deschloro-desmethoxyroseophilin 12 which is the most elaborate derivative of this complex target reported so far.