- Application of diphenyl diselenide as a new catalyst for photochemical stereoisomerization of carotenoids
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In a comparative study, diphenyl diselenide was shown to be an alternative to iodine as a catalyst for photochemical E/Z isomerization of carotenoids. Suitable conditions for the stereomutation of zeaxanthin, violaxanthin, canlhaxanthin and fucoxanthin are reported. Photochemical allenic isomerization with increased R to S conversion was achieved by employing diphenyl diselenide rather than iodine as the catalyst. Reproducible and expedient artificial light conditions, avoiding insolation (sunlight), are reported. Diphenyl diselenide tolerated the presence of Huenig's base upon stereoisomerization of acid-sensitive carotenoids. Diphenyl ditelluride effected E/Z stereomutation, but no allenic R/S isomerization of fucoxanthin. The presence of base decreased the isomerization rate in the absence of catalyst and may serve to decrease undesirable E/Z stereoisomerization of base-stable carotenoids. Acta Chemica Scandinavica 1998.
- Strand, Aase,Liaaen-Jensen, Synnove
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p. 1263 - 1269
(2007/10/03)
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- Carotenoids and related polyenes. Part 3. First total synthesis of fucoxanthin and halocynthiaxanthin using oxo-metallic catalyst
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The first total synthesis of optically active fucoxanthin 1 and halocynthiaxanthin 2 had been accomplished via the 8-oxo compound 5, efficiently prepared by rearrangement of the α-acetylenic alcohol 10 using oxo-metallic catalyst and subsequent iodine-catalysed double-bond shift.
- Yamano, Yumiko,Tode, Chisato,Ito, Masayoshi
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p. 1895 - 1904
(2007/10/02)
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- Total synthesis of photosynthetic pigment fucoxanthin by use of oxo- metallic catalyst
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The first total synthesis of optically active fucoxanthin 1 has been accomplished via the 8-oxo-compound 7, efficiently prepared by rearrangement of the α-acetylenic alcohol 2 using oxo-metallic catalyst and subsequent iodine catalyzed double bond-shift.
- Yamano,Ito
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p. 410 - 412
(2007/10/02)
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