Bactobolin total synthesis

In a total synthesis of (-)-bactobolin, Garigipati and Weinreb used a dichloromethylcerium reagent. The intermediate product (5) was isolated in 34% yield as a single isomer, as shown in Scheme 7. Di chloromethyllithium alone in this reaction afforded intractable material. 

In a total synthesis of the antitumor antibiotic (—)-bactobolin (18), the choice of protecting group on the nitrogen was crucial (eq 10). Unlike other protecting groups, the SES group is compatible with a wide variety of transformations and reagents, and is easily removed at the end of the synthesis. 

---