- Pd(II)-hydrotalcite-catalyzed oxidation of alcohols to aldehydes and ketones using atmospheric pressure of air
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A heterogenized Pd catalyst, Pd(II)-hydrotalcite (palladium(II) acetate-pyridine supported by hydrotalcite) catalyzes the aerobic oxidation in toluene of a variety of primary and secondary alcohols into the corresponding aldehydes and ketones in high yields using atmospheric pressure of air as a sole oxidant under mild conditions. This catalyst is also effective for the oxidation of allylic alcohols, especially such as geraniol and nerol, without any isomerization of an alkenic part. The catalyst can be easily prepared from all commercially available reagents and reused several times.
- Kakiuchi,Maeda,Nishimura,Uemura
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p. 6620 - 6625
(2007/10/03)
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- Syntheses of Cyclopropyl Silyl Ketones
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The synthesis of the cyclopropyl silyl ketones 1-4 is described.The trimethylsilyl ketone 1 was prepared from geraniol ((E)-5) in ca. 10percent overall yield by cyclopropanation leading to 6, CrO3 oxidation to the aldehyde 8, reaction of the latter with trimethylsilyl anion to 14A+B, and CrO3 oxidation to 1.Also for the (t-butyl)dimethylsilyl ketones 2-4, an efficient four-step synthesis with overall yields of 48percent, 85percent, and 13percent, respectively, was elaborated, starting from the allylic alcohols (E)-5, (Z)-5, and 23.The method for the preparation involves as the key step a Wittig rearrangement of the silylalyl ethers ((E/Z)-20, 24) to the silyl alcohols ((E/Z)-21, 25), subsequent cyclopropanation (19A+B, 22A+B, 26), and oxidation to the cyclopropyl silyl ketones 2-4.
- Scheller, Markus E.,Frei, Bruno
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