- Allylic sulfones containing triene moieties as key synthons for carotenoid synthesis
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An efficient synthetic method for the allylic sulfone 2 containing a conjugated triene moiety has been proposed involving i) coupling of allylic sulfones 4 with the C5 bromoallylic sulfide 5, ii) base-promoted dehydrosulfonation in the presence of allylic sulfide, and iii) selective oxidation of the resulting trienyl sulfide to the corresponding sulfone. Total synthesis of lycopene starting from the C15 allylic sulfone 2b has been described, where the new C10 bis(chloroallylic) sulfone 11 proved to be a useful substitute for the C10 bis(chloroallylic) sulfide 3, which did not require the problematic chemoselective sulfur oxidation in a conjugated polyene.
- Ji, Minkoo,Choi, Hojin,Jeong, Young Cheol,Jin, Jingquan,Baik, Woonphil,Lee, Sijoon,Kim, Jeong Soo,Park, Minsoo,Koo, Sangho
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p. 2620 - 2628
(2007/10/03)
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- Selective oxidation of allylic sulfides by hydrogen peroxide with the trirutile-type solid oxide catalyst LiNbMoO6
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Chemoselective sulfur oxidation of allylic sulfides containing double bonds of high electron density due to multiple alkyl substituents or extended conjugation was developed using the composite metal oxide catalyst, LiNbMoO6, without any epoxidation of the electron-rich double bond(s). Selective oxidation to either the corresponding sulfoxides or the sulfones was realized by controlling the stoichiometry of the quantitative oxidant, H202. This new oxidant system had general applicability for chemoselective oxidation of various allylic, benzylic, or propargylic sulfides containing unsaturated carbon-carbon bonds with different electron properties. Various functional groups including hydroxy, formyl, and ethers of THP or TBDMS are compatible under this mild oxidation reaction condition.
- Choi, Soojin,Yang, Jae-Deuk,Ji, Minkoo,Choi, Hojin,Kee, Minyong,Ahn, Kwang-Hyun,Byeon, Song-Ho,Baik, Woonphil,Koo, Sangho
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p. 8192 - 8198
(2007/10/03)
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