title: The 2-(triphenylsilyl)ethoxycarbonyl-("Tpseoc"-) group: a new silicon-based, fluoride cleavable oxycarbonyl protecting group highly orthogonal to the Boc-, Fmoc- and Cbz-groups.
abstract: Starting from 2-(triphenylsilyl)ethanol a new oxycarbonyl protecting group cleavable by fluoride ion induced Peterson-elimination has been developed. Known 2-(triphenylsilyl)ethanol has been prepared from commercially available triphenylvinyl-silane by a hydroboration-oxidation sequence using the sterically hindered borane reagent 9-BBN. The silyl alcohol was subsequently transformed into its chloroformate, imidazolylcarboxylic acid ester and p-nitrophenyl carbonate and used in standard protocols for the formation of carbamates and carbonates. The Tpseoc group proved to be highly resistant against acidic conditions applied in removal of tert-butyl esters and the t-Boc-group. It also withstood catalytic hydrogenation, treatment with morpholine, methylhydrazine and Pd-reagents/allyl-scavanger combinations, conditions required to cleave Cbz-, Fmoc-, phthalimide- and Alloc-groups. The Tpseoc-group is cleaved upon treatment with TBAF/CsF at 0 °C or r.t. with cleavage times reaching from.
authors.affiliation: Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Golkowski
authors.forename: Thomas
authors.initials: T
authors.lastname: Ziegler
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry*; D002625:Chemistry, Organic; D005459:Fluorides / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D005459:Fluorides; D012825:Silicon