High 1,2-Asymmetric Induction in Radical Reactions: Radical Addition toγ-Hydroxyα,β-Unsaturated Carboxylic Esters and Sulfones

Autor:	Motohiro Akazome, Akio Kayano, Katsuyuki Ogura
Rok vydání:	1997
Předmět:	chemistry.chemical_compound chemistry Stereochemistry Benzophenone Stereoselectivity General Chemistry Selectivity Asymmetric induction
Zdroj:	Bulletin of the Chemical Society of Japan. 70:3091-3101
ISSN:	1348-0634 0009-2673
DOI:	10.1246/bcsj.70.3091
Popis:	High 1,2-asymmetric induction was realized by the addition of a 1-hydroxy-1-methylethyl radical to conformationally flexible (E)-γ-hydroxy α,β-unsaturated carboxylic esters and sulfones (1 and 2, respectively). Upon the irradiation (> 290 nm) of (E)-1 and benzophenone in 2-propanol, the 1-hydroxy-1-methylethyl radical was generated in situ and added to (E)-1 with high anti-stereoselectivity. The bulkier is the γ-alkyl group of (E)-1, the higher does the selectivity become. Similarly, a radical addition to the acetates of (E)-1 and (E)-2 proceeded stereoselectively in an anti fashion, whereas (Z)-2 exhibited syn-stereoselectivity. The mechanism for these stereoselective radical additions is discussed.
Databáze:	OpenAIRE
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