113309-44-7Relevant articles and documents
Chiral N-acetyl selone-promoted aldol reactions
Silks III, Louis A.,Kimball, David B.,Hatch, Duane,Ollivault-Shiflett, Morgane,Michalczyk, Ryszard,Moody, Eddie
experimental part, p. 641 - 653 (2009/09/25)
The chiral oxazolidineselone functionality was found to be an excellent partner in the stereospecific acetate aldol reaction with aldehydes via the titanium enolates. Good stereocontrol was obtained as determined by NMR spectroscopy. The oxazolidineselone
Over 98% optical yield achieved by a heterogeneous catalysis. Substrate design and analysis of enantio-differentiating factors of tartaric acid-modified Raney nickel hydrogenation
Sugimura, Takashi,Nakagawa, Satoshi,Tai, Akira
, p. 355 - 363 (2007/10/03)
Tartaric acid-modified Raney nickel (TA-MRNi) is a chiral heterogeneous catalyst for the hydrogenation of prochiral ketones. An optical yield (OY) of 86% with methyl acetoacetate (1) as a substrate was improved to 94-96% by employing β-keto esters having a proper bulkiness at the γ-position. The γ-bulkiness effect contributes to a high intrinsic enantio-differentiating ability (factor-i) of the TA-MRNi catalysis. Through the study, we found the best substrate, γ-cyclopropyl-β-keto ester, the hydrogenation of which resulted in 98.6% OY. This further improvement in the OY was ascribed to a smaller contribution of non-enantio-differentiating hydrogenation (N-site catalysis) due to the substrate-specific activation of the enantio-differentiating hydrogenation by the chiral modifier. The OY of the hydrogenation of 1 was analyzed by comparing with well-behaved β-keto esters, and the contribution of the factor-i and the N-site to the OY value was evaluated to deduce the origin of the enantiodifferentiation.
Efficient enantioselective synthesis of methyl esters of α-unsubstituted β-hydroxy acids via asymmetric aldol-type addition of chiral boron enolates of (methylthio)acetic acid to aldehydes
Fringuelli, Francesco,Piermatti, Oriana,Pizzo, Ferdinando
, p. 1207 - 1211 (2007/10/03)
The aldol-type addition of chiral boron enolates of (methylthio)acetic acid to various aldehydes gives α-(methylthio)-β-hydroxy acids stereoselectively and with good yields. The desulfenylation of methyl esters of the condensation adducts allows methyl es
