title: Nucleophile-catalyzed additions to activated triple bonds. Protection of lactams, imides, and nucleosides with MocVinyl and related groups.
abstract: Additions of lactams, imides, (S)-4-benzyl-1,3-oxazolidin-2-one, 2-pyridone, pyrimidine-2,4-diones (AZT derivatives), or inosines to the electron-deficient triple bonds of methyl propynoate, tert-butyl propynoate, 3-butyn-2-one, N-propynoylmorpholine, or N-methoxy-N-methylpropynamide in the presence of many potential catalysts were examined. DABCO and, second, DMAP appeared to be the best (highest reaction rates and E/Z ratios), while RuCl3, RuClCp*(PPh3)2, AuCl, AuCl(PPh3), CuI, and Cu2(OTf)2 were incapable of catalyzing such additions. The groups incorporated (for example, the 2-(methoxycarbonyl)ethenyl group that we name MocVinyl) serve as protecting groups for the above-mentioned heterocyclic CONH or CONHCO moieties. Deprotections were accomplished via exchange with good nucleophiles: the 1-dodecanethiolate anion turned out to be the most general and efficient reagent, but in some particular cases other nucleophiles also worked (e.g., MocVinyl-inosines can be cleaved with succinimide anion). Some structural and mechanistic details have been accounted for with the help of DFT and MP2 calculations.
authors.affiliation: Departament de Química Orgànica, Facultat de Química, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Catalonia, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Mola
authors.forename: Joan
authors.initials: J
authors.lastname: Font
authors.forename: Lluís
authors.initials: L
authors.lastname: Bosch
authors.forename: Joaquim
authors.initials: J
authors.lastname: Caner
authors.forename: Anna M
authors.initials: AM
authors.lastname: Costa
authors.forename: Gorka
authors.initials: G
authors.lastname: Etxebarría-Jardí
authors.forename: Oriol
authors.initials: O
authors.lastname: Pineda
authors.forename: David
authors.initials: D
authors.lastname: de Vicente
authors.forename: Jaume
authors.initials: J
authors.lastname: Vilarrasa
mesh_terms: D000480:Alkynes / Q000737:chemistry; D002384:Catalysis; D004583:Electrons; D007094:Imides / Q000737:chemistry*; D007288:Inosine / Q000737:chemistry; D007769:Lactams / Q000737:chemistry*; D015394:Molecular Structure; D009025:Morpholines / Q000737:chemistry; D009705:Nucleosides / Q000737:chemistry*; D010879:Piperazines / Q000737:chemistry; D011422:Propionates / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D011728:Pyridones / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D011789:Quantum Theory; D013237:Stereoisomerism; D015215:Zidovudine / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: C417980:4-(dimethylamine)pyridine; D000480:Alkynes; D007094:Imides; D007769:Lactams; D009025:Morpholines; D009705:Nucleosides; D010879:Piperazines; D011422:Propionates; D011725:Pyridines; D011728:Pyridones; D011743:Pyrimidines; D015215:Zidovudine; D007288:Inosine; C017679:2-hydroxypyridine; C011537:propiolic acid; C007306:triethylenediamine