I–-Catalyzed Reaction of 5-Methoxyoxazoles with Organic Iodides – An Efficient Synthesis of Azalactones
作者:Lianghua Lu、Ping Lu、Shengming Ma
DOI:10.1002/ejoc.200600637
日期:2007.2
An I–-catalyzed methoxy carbon–oxygen bond cleavage in 5-methoxyoxazoles leading to the synthesis of azalactones, precursors of quaternary amino acids, has been developed. A series of 4-substituted azalactones were obtained through the variation of the alkyl iodides and differently substituted 5-methoxyoxazoles. Further study indicated that azalactone 3aa may be easily converted to benzoyl-protected
Rhodium-catalyzed heterocycloaddition route to 1,3-oxazoles as building blocks in natural products synthesis
作者:Richard D. Connell、Mark Tebbe、Anthony R. Gangloff、Paul Helquist、Björn Åkermark
DOI:10.1016/s0040-4020(01)87261-6
日期:——
Rhodium(II) acetate serves as a catalyst for the heterocycloaddition reaction of diazodicarbonyl compounds with nitriles to give functionalized 1,3-oxazole derivatives in a simple one-step procedure. In particular, dimethyl diazomalonate undergoes this reaction to give 2-aryl-, 2-alkenyl-, or 2-alkyl-4-carbomethoxy-5-methoxy-1,3-oxazoles, and ethyl formyldiazoacetate (diazomalonate half-ester half-aldehyde)
Rhodium(II) acetate catalyzes the reaction of dimethyl diazomalonate with nitriles to give 4-carbomethoxy-5-methoxy-1,3-oxazo1es. Oxazole formation exceeds cyclopropane formation even in cases of conjugated and non-conjugated unsaturated nitriles.
RhII-catalyzed cycloadditions of carbomethoxy iodonium ylides
作者:Christina Batsila、George Kostakis、Lazaros P Hadjiarapoglou
DOI:10.1016/s0040-4039(02)01260-1
日期:2002.8
Carbomethoxy iodonium ylides, generated from methyl acetoacetate and methyl malonate, respectively, are exploited in synthesis of cyclopropanes, cyclopropenes as well as various heterocycles. (C) 2002 Elsevier Science Ltd. All rights reserved.
GRAZIANO M. L.; IESCE M. R.; CAROTENUTO A.; SCARPATI R., SYNTHESIS, 1977, NO 8, 572-573
作者:GRAZIANO M. L.、 IESCE M. R.、 CAROTENUTO A.、 SCARPATI R.