Phosphine Oxide Catalyzed, Tetrachlorosilane-Mediated Enantioselective Direct Aldol Reactions of Thioesters

Autor:	Sergio Rossi, Rita Annunziata, Laura Raimondi, Franco Cozzi
Rok vydání:	2015
Předmět:	Phosphine oxide organic chemicals Organic Chemistry Hypervalent molecule Enantioselective synthesis Absolute configuration Catalysis chemistry.chemical_compound chemistry Aldol reaction Organic chemistry Lewis acids and bases Enantiomeric excess
Zdroj:	Synthesis. 47:2113-2124
ISSN:	1437-210X 0039-7881
DOI:	10.1055/s-0034-1379914
Popis:	The stereoselective direct aldol reaction of S-phenyl thioesters and aromatic aldehydes promoted by tetrachlorosilane was realized for the first time; the proposed mechanism involves the formation of a chiral cationic hypervalent silicon species and requires the presence of catalytic amounts of a Lewis base, like a chiral phosphine oxide. The reaction affords syn β-hydroxy thioesters as major isomers in good yields, high diastereoselectivity (up to 99:1), and up to 92% enantiomeric excess. The absolute configuration of the major isomer was established by converting the product into the corresponding β-hydroxy ester. The scope of the reaction was also investigated by employing differently substituted thioesters in combination with different aromatic aldehydes.
Databáze:	OpenAIRE
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