- Rhodium-catalyzed asymmetric formal olefination or cycloaddition: 1,3-dicarbonyl compounds reacting with 1,6-diynes or 1,6-enynes
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A cationic rhodium(I) complex catalyzes the title reaction of 1,6-diynes through a [2+2+2] cycloaddition and subsequent electrocyclic ring opening (see scheme; cod=1,5-cyclooctadiene, H8-binap=2,2′- bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1, 1′-binaphthyl). The asymmetric intramolecular [2+2+2] cycloaddition of 1,3-dicarbonyl compounds with 1,6-enynes was also accomplished. Copyright
- Suda, Takeshi,Noguchi, Keiichi,Tanaka, Ken
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p. 4475 - 4479
(2011/06/25)
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- Lewis acid-catalyzed asymmetric hydroxymethylation of silicon enolates in aqueous media
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Asymmetric hydroxymethylation of silicon enolates with formaldehyde in aqueous media has been achieved using praseodymium triflate and a chiral crown ether. Formaldehyde aqueous solution can be directly used for the reactions, and a water/THF mixture was found to be the best solvent system. This is the first example of catalytic asymmetric hydroxymethylation of silicon enolates.
- Manabe, Kei,Ishikawa, Shunpei,Hamada, Tomoaki,Kobayashi, Shu
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p. 10439 - 10444
(2007/10/03)
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