A short synthesis of the unusual amino acid of cyclosporine (4R)-4-[(E)-2-butenyl]-4,N-dimethyl-L-threonine (MeBmt)

Article abstract of DOI:10.1016/0957-4166(94)80034-0

MeBmt 1 was prepared in four steps from the optically pure (2Z, 4R) 4-methyloct-6-yn-2-en-1-ol 8, Z allylic alcohol containing an alkynyl group at the γ position. The two stereogenic centers C-2 and C-3 in the product were controlled using Sharpless' epoxidation and subsequent ring opening at C-2 of the epoxy acid 10 with methylamine.