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Your search keyword '"Chiacchio, Maria A."' showing total 18 results
Start Over Author "Chiacchio, Maria A." Publisher elsevier ltd
18 results on '"Chiacchio, Maria A."'

12. Revealing carbocations in highly asynchronous concerted reactions: The ene-type reaction between dithiocarboxylic acids and alkenes

Author

Chiacchio Maria, A, Legnani, L, Caramella, P, Tejero, T, Merino, P, Chiacchio Maria Assunta, Legnani Laura, Caramella Pierluigi, Tejero T., Merino Pedro, Chiacchio Maria, A, Legnani, L, Caramella, P, Tejero, T, Merino, P, Chiacchio Maria Assunta, Legnani Laura, Caramella Pierluigi, Tejero T., and Merino Pedro

Abstract

The ene-type reaction between (dithio)carboxylic acids and alkenes has been studied computationally by DFT and topological (analysis of the electron localization function, ELF) methods. The reaction proceeds under kinetic control and the observed differences in regioselectivity are well-explained by the relative stability of the different transition structures. In agreement with experimental observations, electron-rich alkenes lead to Markownikoff adducts while electron-poor alkenes lead to Michael adducts. In all cases the reaction proceeds through an only transition structure (one kinetic step) although a different synchronicity was observed depending on the alkene electronics. The ELF analysis of the reactions corroborates the existence of a transient carbocation (hidden intermediate) in the reactions with electron-rich alkenes. On the other hand, electron-poor alkenes proceed through a more synchronous concerted mechanism. It can be predicted that with electron-rich alkenes bearing highly donating the transient carbocations might be captured by a nucleophile.

Published
2018

16. Synthesis and conformational analysis of a simplified inositol-model of the Streptococcus pneumoniae 19F capsular polysaccharide repeating unit

Author

Catelani, G, D'Andrea, F, Guazzelli, L, Griselli, A, Testi, N, Chiacchio, M, Legnani, L, Toma, L, Catelani, Giorgio, D'Andrea, Felicia, Guazzelli, Lorenzo, Griselli, Alessio, Testi, Nicola, Chiacchio, Maria Assunta, LEGNANI, LAURA, TOMA, LUCIO, Catelani, G, D'Andrea, F, Guazzelli, L, Griselli, A, Testi, N, Chiacchio, M, Legnani, L, Toma, L, Catelani, Giorgio, D'Andrea, Felicia, Guazzelli, Lorenzo, Griselli, Alessio, Testi, Nicola, Chiacchio, Maria Assunta, LEGNANI, LAURA, and TOMA, LUCIO

Abstract

Carbohydrate mimics have been studied for a long time as useful sugar substitutes, both in the investigation of biological events and in the treatment of sugar-related diseases. Here we report further evaluation of the capabilities of inositols as carbohydrate substitutes. The conformational features of an inositol-model of a simplified repeating unit corresponding to the capsular polysaccharide of Streptococcus pneumoniae 19F has been evaluated by computational analysis, and compared to the native repeating unit. The inositol mimic was synthesized, and its experimental spectroscopic data allowed for verification of the theoretical results.

Published
2017

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