制备 de l'enantiomere naturel de l'acide N-乙酰神经氨酸 a partir du phenylseleno-2 propanal et du benzyloxy-4 [furyl-2]-1 methoxy-1 trimethylsiloxy-3 butadiene-«1,3»。L'enantiomere du KDO est obtenu a partir du phenylseleno-2 propionate demethyle
[2,3]-Sigmatropic Rearrangement of Allylic Selenimides: Strategy for the Synthesis of Peptides, Peptidomimetics, and <i>N</i>-Aryl Vinyl Glycines
作者:Alan Armstrong、Daniel P. G. Emmerson、Harry J. Milner、Robert J. Sheppard
DOI:10.1021/jo500341e
日期:2014.5.2
The scope of the NCS-mediated amination/[2,3]-sigmatropicrearrangement of enantioenriched allylic selenides has been expanded to provide access to three new product classes. The use of N-protected amino acid amides provides a novel strategy for accessing peptide chains containing unnatural vinyl glycine amino acid residues. Also reported is the use of amino acid esters, allowing the diastereoselective
Polystyrene-supported organocatalysts for α-selenenylation and Michael reactions
作者:Francesco Giacalone、Michelangelo Gruttadauria、Paola Agrigento、Vincenzo Campisciano、Renato Noto
DOI:10.1016/j.catcom.2011.08.040
日期:2011.11
Three different resin-supported catalysts have been prepared by using the well established post-modification approach by means of thiol-ene coupling reaction. Two catalysts were tested for the first time in the asymmetric alpha-selenenylation of propanal, while the third catalyst was used in the Michael addition reaction. While the preliminary results are not encouraging in the case of supported Jorgensen' catalyst, interesting data have been collected with both for the supported MacMillan and prolyl-prolinol catalysts. In fact, these catalysts displayed good activity and selectivity. A reversed enantioselectivity in the alpha-selenenylation was observed by changing the polarity of the solvent. Finally, these materials were easily recovered, and used four and five times, respectively. (C) 2011 Elsevier B.V. All rights reserved.
Organocatalytic Asymmetric α-Selenenylation of Aldehydes