Convenient Methods for the Preparation of Unsymmetrical Double Aldols

Autor:	Teruaki Mukaiyama, Khanitha Pudhom, Keiko Yamane, Hidehiro Arai
Rok vydání:	2003
Předmět:	chemistry.chemical_classification Addition reaction Ketone Chemistry Aryl chemistry.chemical_element General Chemistry General Medicine Ring (chemistry) Medicinal chemistry Aldehyde Samarium chemistry.chemical_compound Aldol reaction Organic chemistry Alkyl Titanium
Zdroj:	ChemInform. 34
ISSN:	1522-2667 0931-7597
DOI:	10.1002/chin.200319035
Popis:	Double aldol reaction proceeded stereoselectively at one α-carbon of ketones to give α-(1-hydroxyalkyl)-β-hydroxyalkyl ketones (double aldols) in good to high yields by the following three methods: i) tin(II) trifluoromethanesulfonate-mediated aldol reaction of aldehydes with β-hydroxy ketones (mono-aldols) in the presence of tertiary amines, ii) samarium(II) iodide-mediated aldol reaction of aldehydes with alkyl or aryl oxiranyl ketones, iii) Sn(OTf)2-promoted aldol reaction of α-bromo ketones with aldehydes giving α-bromo-β-stannyloxy ketones which were then converted to titanium enolates on treatment with low-valent titanium. Double aldols were formed by subsequent reaction of the above titanium enolates with aldehydes in one-pot procedure. Further, small and medium-sized carbocyclic compounds whose ring skeletons were composed of double aldol structure were synthesized by SmI2-mediated intramolecular cyclization between oxiranyl ketone and aldehyde functions.
Databáze:	OpenAIRE
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