Nucleophile-Catalyzed Additions to Activated Triple Bonds. Protection of Lactams, Imides, and Nucleosides with MocVinyl and Related Groups

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• 作者：Laura Mola ; Joan Font ; Llu铆s Bosch ; Joaquim Caner ; Anna M. Costa ; Gorka Etxebarr铆a-Jard铆 ; Oriol Pineda ; David de Vicente ; Jaume Vilarrasa
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：June 21, 2013
• 年：2013
• 卷：78
• 期：12
• 页码：5832-5842
• 全文大小：396K
• 年卷期：v.78,no.12(June 21, 2013)
• ISSN：1520-6904

文摘

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.