Base-Promoted Isomerization of <i>cis</i>-4-Formyl-2-azetidinones: Chemoselective <i>C</i>4-Epimerization vs Rearrangement to Cyclic Enaminones
作者:Benito Alcaide、Moustafa F. Aly、Carolina Rodríguez、Alberto Rodríguez-Vicente
DOI:10.1021/jo991984h
日期:2000.6.1
N-(p-methoxyphenyl)-beta-lactams can be used, and (ii) transformation is less compatible with heteroatomic substituents bonded to the C3 position of the 2-azetidinone ring. A highly general solution to these problems relies on the use of sodium carbonate as the isomerization reagent in different solvents. We also describe a novel base-promotedrearrangement of the beta-lactam ring to cyclic enaminones 6
Synthesis of 4-Diarylamino-3-iodo-2(5<i>H</i>)-furanones via the Simultaneous <font>α</font>-Iodination and <i>N</i> <sup> <font>β</font> </sup>-Arylation by an Efficient Difunctionalizable Transfer Reagent PhI(OAc)<sub>2</sub>
作者:Fuling Xue、Pai Peng、Jie Shi、Mingli Zhong、Zhaoyang Wang
DOI:10.1080/00397911.2013.879899
日期:2014.7.3
intramolecular cyclization of 4-arylamino-2(5H)-furanones via the Pd-catalyzed C-H activation, a kind of difunctionalization reaction caused by the designed oxidant PhI(OAc)2 [(diacetoxyiodo)benzene, DIB] was accidentally discovered. When 1.5 eq. DIB is used as a difunctionalizable transfer reagent in the 40 h reaction at 60°C and CH3CN as solvent, 4-diarylamino-3-iodo-2(5H)-furanones can be obtained with
An Efficient and Selective Pd-catalyzed Dehalogenation Reaction
作者:Fu-Ling Xue、Ji Qi、Pai Peng、Guang-Zhen Mo、Zhao-Yang Wang
DOI:10.2174/15701786113109990041
日期:2014.1.31
During the research on the Pd-catalyzed intramolecular cyclization reaction via C-H activation, the dehalogenation
of 3-halo-2(5H)-furanones is unexpectedly discovered. Under the optimized conditions without any special anaerobic
and anhydrous treatments, using N,N-diisopropylethylamine (DIPEA) simultaneously as hydrogen source and base, the
reactions of 27 substrates with less Pd catalyst (5 mol% Pd(PPh3)4) usually give higher yields (70-99%, mostly over 82%).
Especially for 3-halo-2(5H)-furanone substrates simultaneously containing aryl halide structure, this kind of Pd-catalyzed
dehalogenation has good selectivity. After the selectivity is explained via the substrate theoretical calculation, a possible
reaction mechanism of the Pd-catalyzed dehalogenation is proposed. These novel investigations provide an efficient, simple,
practical and selective Pd-catalyzed dehalogenation method for the non-aromatic halide substrates with many
different functional groups.