Abstract
The first enantioselective synthesis of the Fmoc-protected rare amino acid, 3,4-dimethyl-2-(methylamino)pentanoic
acid, is disclosed. The synthesis utilized the chiral oxazolidinone to introduce the
first chiral center (>95:5 ee), and then swapped the auxiliary to Ellman’s N-sulfinylimine for setting up the chiral α-amino group (95:5 dr). The newly formed
chiral centers were confirmed by X-ray crystallography. With this unique amino acid
on hand, naturally occurring macrocyclic peptides will become synthetically accessible.
Key words
enantioselective synthesis - amino acid - etamycins A - triostin C - echinomycin C
