Proline-Catalyzed Ketone-Aldehyde Aldol Reactions are Accelerated by Water
作者:Petri Pihko、Annika Nyberg、Annina Usano
DOI:10.1055/s-2004-831296
日期:——
Proline-catalyzed aldol reactions between acetone or 4-thianone and different aldehydes are accelerated by addition of 1-10 equivalents of water to the reaction medium, allowing stoichiometric aldol reactions to proceed at acceptable rates.
Improved Conditions for the Proline-Catalyzed Aldol Reaction of Acetone with Aliphatic Aldehydes
作者:Benjamin List、Alberto Martínez、Kristina Zumbansen、Arno Döhring、Manuel van Gemmeren
DOI:10.1055/s-0033-1340919
日期:——
The proline-catalyzed asymmetric aldol reaction between aliphatic aldehydes and acetone has, to date, remained underdeveloped. Challenges in controlling this reaction include avoiding undesired side reactions such as aldol condensation and self-aldolization. In recent years we have developed optimized conditions, which enable high yields and good to excellent enantioselectivities, and which are presented
The reversal of the enantioselectivity in the heterogeneous asymmetric direct aldol reactions obtained over resin supported di- versus tripeptides was studied in a continuous-flow system.
在连续流系统中研究了树脂支持的二肽与三肽在不对称直接醛醇反应中对映选择性的逆转。
Contrasting steric effects of the ketones and aldehydes in the reactions of the diisopinocampheyl enolborinates of methyl ketones with aldehydes
作者:P.Veeraraghavan Ramachandran、Wei-chu Xu、Herbert C. Brown
DOI:10.1016/0040-4039(96)00969-0
日期:1996.7
representative series of aldehydes, both of differing steric requirements provides aldols whose enantiomeric purities depend on the steric requirements of both the ketones and the aldehydes. This study has shown that increasing the steric requirements of the R group in the ketones has a pernicious effect on the ee, while increasing the steric requirements of the R group in the aldehydes exerts a beneficial
Dipeptide-catalyzed direct asymmetric aldol reactions in the presence of water
作者:Meng Lei、Lanxiang Shi、Gong Li、Shilv Chen、Weihai Fang、Zemei Ge、Tieming Cheng、Runtao Li
DOI:10.1016/j.tet.2007.05.077
日期:2007.8
dipeptide has been discovered and developed as an efficient catalyst for the directasymmetricaldolreactions of unmodified ketones with various aldehydes including aromatic, aliphatic, heteroaromatic, and unsaturated aldehydes in the presence of water at 0 °C. The resulted methodology and optimal conditions led to the corresponding aldol products with high yields (up to 94%) and good enantioselectivities