- Stereochemistry and Side Products in Reductive Coupling of Alkyl Aryl Ketones to 1,2-Dialkyl-1,2-diarylethylenes
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The reductive coupling of alkyl aryl ketones 1 - 3 and 7 - 9 by low valent titanium salts yields predominantly the (Z)-isomers of 11 - 13 and 17 - 19.Evidence is given by 1H NMR spectroscopy.This behavior can be explained by ?-complex formation of phenyl rings with Ti0.Severe steric hindrance, however, favors the (E)-isomers ( -> 14 and 15).Donor groups in p-position, particularly, give increasing amounts of pinacols, 23 - 27, which undergo rearrangement to the ketones 28 and 29.
- Leimner, Juergen,Weyerstahl, Peter
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p. 3697 - 3705
(2007/10/02)
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