A set of enantiomerically pure Lewis bases containing different diphenyl phosphinyl oxide groups were easily synthesized in a straightforward procedure by reaction of readily available proline-based scaffolds and phosphinoyl chlorides. The newly synthesized derivatives were employed (0.1 mol equiv) as organocatalysts in the Lewis acid-mediated Lewis base-promoted direct stereoselective aldol reactions of activated thioesters with aromatic aldehydes, carried out in the presence of tetrachlorosilane and a tertiary amine. β-Hydroxy thioesters were obtained in moderate to high yields, with very high syn diastereoselectivities (dr up to >98:2), and fair enantioselectivities (ee up to 51%). Theoretical studies were performed in order to elucidate the origin of the stereoselection.
Readily available (S)-proline-derived organocatalysts for the Lewis acid-mediated Lewis base-catalyzed stereoselective aldol reactions of activated thioesters / M. Bonsignore, M. Benaglia, F. Cozzi, A. Genoni, S. Rossi, L. Raimondi. - In: TETRAHEDRON. - ISSN 0040-4020. - 68:39(2012), pp. 8251-8255.
|Titolo:||Readily available (S)-proline-derived organocatalysts for the Lewis acid-mediated Lewis base-catalyzed stereoselective aldol reactions of activated thioesters|
BONSIGNORE, MARTINA (Primo)
BENAGLIA, MAURIZIO (Secondo)
ROSSI, SERGIO (Penultimo)
RAIMONDI, LAURA MARIA (Ultimo)
|Parole Chiave:||Lewis base; Organocatalysis; Phosphoroamide; Tetrachlorosilane; Thioesters|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||2012|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.tet.2012.07.062|
|Appare nelle tipologie:||01 - Articolo su periodico|