Toward an integrated route to the vernonia allenes and related sesquiterpenoids

• Da Xu,
• Michael A. Drahl and
• Lawrence J. Williams

Beilstein J. Org. Chem. 2011, 7, 937–943, doi:10.3762/bjoc.7.104

• Da Xu Michael A. Drahl Lawrence J. Williams Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854, USA 10.3762/bjoc.7.104 Abstract The synthesis of a model endocyclic allene related to the vernonia allenes is described

• present sequence are also discussed. Keywords: C–C fragmentation; endocyclic allene; natural product; total synthesis; Introduction Well over 150 allene-containing natural products are known [1][2][3][4][5]. Among these, intriguing complex structures were assigned by Bohlmann and co-workers to isolates

• from the aerial parts of Vernonia species collected mainly from northern Brazil about 30 years ago (1–3, Figure 1) [6][7][8]. These bicyclic germacranolides are the only known endocyclic allene-containing natural products. Interestingly, no synthetic studies of these complex natural products have been