Unusual Reactivity of Dimethylsulfoxonium Methylide with Esters
作者:Antonella Leggio、Rosaria De Marco、Francesca Perri、Mariagiovanna Spinella、Angelo Liguori
DOI:10.1002/ejoc.201101031
日期:2012.1
The dimethylsulfoxonium methylide was treated with esters under mild conditions to rapidly afford the corresponding carboxylic acids at room temperature. Moreover, by performing the procedure on enantiopure substrates, it was demonstrated that the reaction occurs without racemization. 18O-labeled reagents showed that the reaction does not proceed through an ester hydrolysis mechanism. The reactions
N-(4-Nitrophenylsulfonyl)- and N-(Fluorenylmethoxycarbonyl)-N-ethyl Amino Acid Methyl Esters - A Practical Approach
作者:Emilia Lucia Belsito、Rosaria De Marco、Maria Luisa Di Gioia、Angelo Liguori、Francesca Perri、Maria Caterina Viscomi
DOI:10.1002/ejoc.201000256
日期:2010.8
An efficient one-pot preparation of N-ethyl-N-4-nitrophenylsulfonyl (nosyl) aminoacid methyl esters was accomplished by a simple N-ethylation reaction by using triethyloxonium tetrafluoroborate in the presence of N,N-diisopropylethylamine. The N-ethylated aminoacid methyl esters are obtained with total retention of stereochemistry at the original chiral centers. To further broaden the scope of this