A Mixed‐Ligand Chiral Rhodium(II) Catalyst Enables the Enantioselective Total Synthesis of Piperarborenine B. (15th March 2016)

• Record Type: Journal Article
• Authors: Panish, Robert A.; Chintala, Srinivasa R.; Fox, Joseph M.
• Is Part Of: Angewandte Chemie. Volume 128:Number 16(2016)
• Page Start: 5067
• Page End: 5071
• Publication Date: 2016-03-15
• Subjects: Bicyclobutan -- Chirale Rhodiumkatalysatoren -- Gespannte Moleküle -- Homokonjugierte Additionen -- Piperarborenin B; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201600766
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A novel, mixed‐ligand chiral rhodium(II) catalyst, Rh2 (S‐NTTL)3 (dCPA), has enabled the first enantioselective total synthesis of the natural product piperarborenine B. A crystal structure of Rh2 (S‐NTTL)3 (dCPA) reveals a "chiral crown" conformation with a bulky dicyclohexylphenyl acetate ligand and three N‐naphthalimido groups oriented on the same face of the catalyst. The natural product was prepared on large scale using rhodium‐catalyzed bicyclobutanation/ copper‐catalyzed homoconjugate addition chemistry in the key step. The route proceeds in ten steps with an 8 % overall yield and 92 % ee .