Proline-Catalyzed Asymmetric Aldol Reactions between Ketones and α-Unsubstituted Aldehydes
作者:Benjamin List、Peter Pojarliev、Chris Castello
DOI:10.1021/ol006976y
日期:2001.2.1
[reaction: see text] With this communication we extend the methodology of proline-catalyzed direct asymmetric aldol reactions to include alpha-unsubstituted aldehydes as acceptors. This important aldehyde class gives the corresponding aldols in 22-77% yield and up to 95% ee when the reactions are performed in pure acetone or in ketone/chloroform mixtures. On the basis of these results we have developed
Amino Acid Catalyzed Direct Asymmetric Aldol Reactions: A Bioorganic Approach to Catalytic Asymmetric Carbon−Carbon Bond-Forming Reactions
作者:Kandasamy Sakthivel、Wolfgang Notz、Tommy Bui、Carlos F. Barbas
DOI:10.1021/ja010037z
日期:2001.6.1
lack of nonlinear effects. The reactions tolerate a small amount of water (<4 vol %), do not require inert reaction conditions and preformed enolate equivalents, and can be conveniently performed at room temperature in various solvents. In addition, reaction conditions that facilitate catalyst recovery as well as immobilization are described. Finally, mechanistically related addition reactions such as
Development of an Effective Chiral Auxiliary for Hydroxyalkyl Radicals
作者:Philip Garner、James T. Anderson、Philip B. Cox、Stephen J. Klippenstein、Ray Leslie、Noemi Scardovi
DOI:10.1021/jo010880f
日期:2002.8.1
development of an effective chiral auxiliary for hydroxyalkylradicals is delineated. Both the 2-tetrahydropyranyl (THP) and tri-O-benzyl-2-deoxy-alpha-D-glucopyranosyl (GLU) auxiliaries resulted in diastereoselective radical additions to methyl acrylate at -78 degrees C (ds = 6/1 and 11/1, respectively). The developing stereochemistry at the radical center was completely under auxiliary control. Correlation
Conversion of Conjugated Enones into Enantiomerically Pure -Hydroxy Ketones or 1,3-Diols - Samarium(II) Bromide Reductions of Protected ,-Dihydroxy Ketones
作者:Andreas Zörb、Reinhard Brückner
DOI:10.1002/ejoc.201000279
日期:2010.9
Asymmetric dihydroxylations of α,β-unsaturated ketones in the presence of Sharpless' AD mix-β™ delivered α,β-dihydroxy ketones or, if phenylboronic acid was present, the corresponding phenylboronates. The C α ―O bonds of these species were removed at ―78 °C ― in the former case after acetonide formation, in the latter case directly ― in an unprecedented manner, namely by treatment with a suspension
在 Sharpless 的 AD mix-β™ 存在下,α,β-不饱和酮的不对称二羟基化产生 α,β-二羟基酮,如果存在苯基硼酸,则生成相应的苯基硼酸酯。这些物种的 C α -O 键在 -78 °C 下被去除 - 在前一种情况下是在丙酮化物形成后,在后一种情况下直接 - 以前所未有的方式,即通过用 Sm II 溴化物在 THF/MeOH 中的悬浮液处理. 如果需要,可以还原所得的单羟基酮以得到顺式或反式构型的 1,3-二醇。在 0 °C 下用 Sm II 溴化物一锅还原 α,β-二羟基酮双丙酮化物,产生相同的二醇。当同样处理α,β-二羟基酮苯基硼酸酯时,得到1,3-二醇的苯基硼酸酯。
FRUCTOSE-6-PHOSPHATE ALDOLASE VARIANTS FOR ALDOL CARBOLIGATIONS
申请人:Consejo Superior de Investigaciones Científicas
(CSIC)
公开号:EP3388518A1
公开(公告)日:2018-10-17
The invention provides new and alternative fructose-6-phosphate aldolase (FSA) variants which enable the production of optically active building blocks with high chemoselectivity and stereoselectivity using aldehydes as starting material in aldol carboligation reactions, while avoiding the by-product formation and subsequent reactions.