Modified Julia-Kocienski Reagents for a Stereoselective Introduction of Trisubstituted Double Bonds: A Formal Total Synthesis of Limazepine E and Barmumycin.

A formal total synthesis of pyrrolo[1,4]benzodiazepine anticancer antibiotic family member limazepine E is described. The synthesis features a stereoselective introduction of a trisubstituted double bond using novel sterically demanding Julia-Kocienski reagents, allowing the number of linear steps to be significantly reduced. The potential of the newly developed reagents has also been demonstrated by the formal total synthesis of barmumycin.