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.
The application of a structurally simple, recyclable, and large-scale l-prolinamide catalyst for asymmetric aldol reactions
作者:Zhi Guan、Yuan Luo、Bao-Qiang Zhang、Krystal Heinen、Da-Cheng Yang、Yan-Hong He
DOI:10.1016/j.tetasy.2014.04.009
日期:2014.5
With heterocyclic ketones or cyclohexanone, the aldolreactions gave products in high yields and with respectable enantioselectivities (87–99% ee) and diastereoselectivities (up to >99:1 anti/syn). The catalyst could be recycled and reused up to seven times resulting in good yields and with good selectivities. This catalyst is also efficient in large-scale reactions with the enantioselectivities remaining
Effect of additives on the proline-catalyzed ketone–aldehyde aldol reactions
作者:Petri M. Pihko、Katri M. Laurikainen、Annina Usano、Annika I. Nyberg、Jatta A. Kaavi
DOI:10.1016/j.tet.2005.09.070
日期:2006.1
The effect of bases, acids, and water as additives in proline-catalyzed ketone–aldehyde aldol reactions has been studied. While the reaction appears to be relatively tolerant to small amounts of tertiary amine bases or weak acids, it stops completely with strong acids. The use of water as an additive had a highly beneficial effect on reactions that were conducted with a stoichiometric ratio of ketone
On the Origin of Dolabriferol: Total Synthesis via Its Putative Contiguous Precursor
作者:Athanasios Karagiannis、Naveen Diddi、Dale E. Ward
DOI:10.1021/acs.orglett.6b01798
日期:2016.8.5
The putative contiguous polypropionate precursor of dolabriferol was synthesized using as the key step a rationally designed enantiomer-selective aldol coupling (i.e., with kinetic resolution) of a racemic C1–C8 ketone fragment with an enantiopure C9–C15 aldehyde fragment. When exposed to alumina, the precursor was cleanly transformed into dolabriferol via a regioselective retro-Claisen fragmentation
Highly diastereoselective aldol reactions of 4-thianone: a new strategy for synthesis of polypropionate frames
作者:Toshio Hayashi
DOI:10.1016/s0040-4039(00)92388-8
日期:1991.9
The aldolreactions of the lithium enolate of 4-thianone with aldehydes yield the threo-isomers of aldols in a highly stereoselective manner and also showed high diastereoface selectivity. Other metal enolates of this reagent exhibited different behabiors from those of the corresponding cyclohexane enolates.