title: Asymmetric Synthesis of Calyculin C. 2. Synthesis of the C(26)-C(37) Fragment and Model Wittig Couplings.
abstract: We report our synthesis of the C(26)-C(37) fragment of serine/threonine protein phosphatase PP1 and PP2A inhibitor calyculin C (1). Outlined in this paper are synthetic approaches to the two components based on disconnection at the C(33)-N(3) amide bond. We report the successful synthesis of the C(33)-C(37) aza-sugar derived from D-lyxose which was coupled onto a C(26)-C(32) aminooxazole originating from L-pyroglutamic acid. Elaboration of the resulting amide to a fully deprotected C(26)-C(37) fragment of calyculin C completed our synthesis. This provided an appropriate phosphonium salt for use in a Wittig olefination for joining both halves of the natural product.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, 90095.
authors.forename: Anthony K.
authors.initials: AK
authors.lastname: Ogawa
authors.forename: John A.
authors.initials: JA
authors.lastname: DeMattei
authors.forename: Gerard R.
authors.initials: GR
authors.lastname: Scarlato
authors.forename: John E.
authors.initials: JE
authors.lastname: Tellew
authors.forename: Lee S.
authors.initials: LS
authors.lastname: Chong
authors.forename: Robert W.
authors.initials: RW
authors.lastname: Armstrong