Furanosides and furanones bearing acrylate sidechains via palladium-mediated cyclizations of γ-Oxoallenes
摘要:
Treatment of 4,5-hexadienal with catalytic palladium(II) chloride and excess copper(II) chloride, methanol and carbon monoxide in the presence of an acid and a water scavenger resulted in a net acetalization-cyclization-methoxycarbonylation to form a novel methyl furanoside bearing a methyl acrylate sidechain. Treatment of 4,5-hexadienoic acid under the same conditions yields the corresponding furanone, and 3-(tert-butylidimethylsilyloxy)-4,5-hexadienal yields a methyl beta-3'-(tert-butyldimethylsilyloxy)-2'-deoxyribofuranoside bearing the acrylate sidechain, with high stereoselectivity. This methodology provides access to sidechain-branched ribofuranoside compounds.
Furanosides and furanones bearing acrylate sidechains via palladium-mediated cyclizations of γ-Oxoallenes
摘要:
Treatment of 4,5-hexadienal with catalytic palladium(II) chloride and excess copper(II) chloride, methanol and carbon monoxide in the presence of an acid and a water scavenger resulted in a net acetalization-cyclization-methoxycarbonylation to form a novel methyl furanoside bearing a methyl acrylate sidechain. Treatment of 4,5-hexadienoic acid under the same conditions yields the corresponding furanone, and 3-(tert-butylidimethylsilyloxy)-4,5-hexadienal yields a methyl beta-3'-(tert-butyldimethylsilyloxy)-2'-deoxyribofuranoside bearing the acrylate sidechain, with high stereoselectivity. This methodology provides access to sidechain-branched ribofuranoside compounds.
A palladium-catalyzed cyclization-carbonylation-coupling reaction between aryl halides and γ-Hydroxyallenes to form aryl (tetrahydrofuran-2-yl)vinyl ketones
作者:Robert D. Walkup、Lufeng Guan、Young Soo Kim、Sang Woong Kim
DOI:10.1016/0040-4039(95)00666-z
日期:1995.5
γ-Hydroxyallenes undergo cyclization-carbonylation-coupling with aryl (and one alkenyl) halides in the presence of catalytic Pd(PPh3)4, base, and CO to form the title ketones in good yields. The reaction was temperature dependent: at 80 °C, the CO insertion did not readily occur, while at 55–60 °C the ketone products predominated. Yields for the Pd(0)-catalyzed cyclization-coupling reaction (without
Access to -2,5-disubstituted iodovinyltetrahydrofurans via the cyclization of γ-silyloxyallenes using n-iodosuccinimide
作者:Robert D Walkup、Lufeng Guan、Sang Woong Kim、Young Soo Kim
DOI:10.1016/0040-4039(92)88075-g
日期:1992.7
Treatment of gamma-(tert-butyldimethylsiloxy)- or gamma-(trimethylsiloxy)allenes bearing various groups at the ether carbon with N-iodosuccinimide resulted in the formation of iodocyclization products, 1-iodo-1-(tetrahydrofuran-2'-yl)ethenes, in good yields and with high selectivity for the cis diastereomer.
Furanosides and furanones bearing acrylate sidechains via palladium-mediated cyclizations of γ-Oxoallenes
作者:Robert D. Walkup、Michael D. Mosher
DOI:10.1016/0040-4020(93)80015-l
日期:1993.1
Treatment of 4,5-hexadienal with catalytic palladium(II) chloride and excess copper(II) chloride, methanol and carbon monoxide in the presence of an acid and a water scavenger resulted in a net acetalization-cyclization-methoxycarbonylation to form a novel methyl furanoside bearing a methyl acrylate sidechain. Treatment of 4,5-hexadienoic acid under the same conditions yields the corresponding furanone, and 3-(tert-butylidimethylsilyloxy)-4,5-hexadienal yields a methyl beta-3'-(tert-butyldimethylsilyloxy)-2'-deoxyribofuranoside bearing the acrylate sidechain, with high stereoselectivity. This methodology provides access to sidechain-branched ribofuranoside compounds.