71699-15-5Relevant academic research and scientific papers
Tetrahedral boronates as basic catalysts in the aldol reaction
Müller, Tobias,Djanashvili, Kristina,Peters, Joop A.,Arends, Isabel W.C.E.,Hanefeld, Ulf
, p. 587 - 595 (2016/02/12)
β-Hydroxyketones are versatile building blocks in organic synthesis, which can be conveniently synthesized from ketones and aldehydes by aldol reactions. Unfortunately, these reactions often suffer from dehydration of the initially formed β-hydroxyketones
Synthesis of (+)-discodermolide by catalytic stereoselective borylation reactions
Yu, Zhiyong,Ely, Robert J.,Morken, James P.
supporting information, p. 9632 - 9636 (2014/10/15)
The marine natural product (+)-discodermolide was first isolated in 1990 and, to this day, remains a compelling synthesis target. Not only does the compound possess fascinating biological activity, but it also presents an opportunity to test current methods for chemical synthesis and provides an inspiration for new reaction development. A new synthesis of discodermolide employs a previously undisclosed stereoselective catalytic diene hydroboration and also establishes a strategy for the alkylation of chiral enolates. Furthermore, this synthesis of discodermolide provides the first examples of the asymmetric 1,4-diboration of dienes and borylative diene-aldehyde couplings in complex-molecule synthesis. Borylation-based synthesis: The development of a strategy for stereocontrol in catalytic diene hydroboration enables the synthesis of a critical building block for the assembly of (+)-discodermolide. Combined with asymmetric catalytic diboration, hydroformylation, and borylative aldehyde-diene coupling reactions, (+)-discodermolide could then be prepared from simple hydrocarbon-based building blocks.
Investigation of a novel diamine based chiral auxiliary in the asymmetric alkylation of ketones
Clarke, Sarah L.,McSweeney, Christina M.,McGlacken, Gerard P.
, p. 356 - 361 (2014/04/03)
A novel chiral auxiliary containing a pyrrolidine ring has been utilised in the preparation of various chiral ketones with good to excellent enantioselectivities (up to 92%). It has been successfully employed in aldol and Michael reactions giving moderate to high selectivity.
Rh-catalyzed aldehyde - Aldehyde cross-aldol reaction under base-free conditions: In situ aldehyde-derived enolate formation through orthogonal activation
Lin, Luqing,Yamamoto, Kumiko,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 2974 - 2983 (2014/01/06)
The chemoselective generation of aldehyde-derived enolates to realize an aldehyde - aldehyde cross-aldol reaction is described. A combined Rh/dippf system efficiently promoted the isomerization/aldol sequence by using primary allylic, homoallylic, and bishomoallylic alcohols; secondary allylic and homoallylic alcohols; and trialkoxyboranes that were derived from primary allylic and homoallylic alcohols. The reaction proceeded at ambient temperature under base-free conditions, thus giving cross-aldol products with high chemoselectivity. Mechanistic studies, as well as its application to double-aldol processes under protecting-group-free conditions, are also described. Copyright
Gallium(III) triflate catalyzed diastereoselective mukaiyama aldol reaction by using low catalyst loadings
Plancq, Baptiste,Justafort, Lyse Carole,Lafantaisie, Mathieu,Ollevier, Thierry
supporting information, p. 6525 - 6529 (2013/11/06)
A mild method for the diastereoselective Mukaiyama aldol reaction is reported. By using a low loading of the gallium(III) triflate catalyst (down to 0.01 mol-%), the transformation proceeds efficiently to afford the corresponding β-hydroxy ketones in yields up to 92a€‰%. To the best of our knowledge, this is the first report of a metal triflate acting as a safe, bench-stable, and slow-releasing source of triflic acid for the Mukaiyama aldol reaction. A diastereoselective Mukaiyama aldol reaction was performed under mild conditions with a low loading of the gallium(III) triflate catalyst (down to 0.01 mol-%). The transformation proceeded efficiently to afford the corresponding β-hydroxy ketones in yields up to 92a€‰%. Copyright
Iron- and bismuth-catalyzed asymmetric mukaiyama aldol reactions in aqueous media
Kitanosono, Taku,Ollevier, Thierry,Kobayashi, Shu
supporting information, p. 3051 - 3062 (2014/01/06)
We have developed asymmetric Mukaiyama aldol reactions of silicon enolates with aldehydes catalyzed by chiral FeII and BiIII complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (-78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water-compatible Lewis acids for the Mukaiyama aldol reaction, many Lewis acids were screened in combination with chiral bipyridine L1, which had previously been found to be a suitable chiral ligand in aqueous media. Three types of chiral catalysts that consisted of a FeII or BiIII metal salt, a chiral ligand (L1), and an additive have been discovered and a wide variety of substrates (silicon enolates and aldehydes) reacted to afford the desired aldol products in high yields with high diastereo- and enantioselectivities through an appropriate selection of one of the three catalytic systems. Mechanistic studies elucidated the coordination environments around the FeII and BiIII centers and the effect of additives on the chiral catalysis. Notably, both Bronsted acids and bases worked as efficient additives in the Fe II-catalyzed reactions. The assumed catalytic cycle and transition states indicated important roles of water in these efficient asymmetric Mukaiyama aldol reactions in aqueous media with the broadly applicable and versatile catalytic systems. Copyright
Rhodium-catalyzed cross-aldol reaction: In situ aldehyde-enolate formation from allyloxyboranes and primary allylic alcohols
Lin, Luqing,Yamamoto, Kumiko,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 10275 - 10279,5 (2012/12/12)
Dip in. A Rh/dippf catalyst generates aldehyde-derived enol boranes at ambient temperature by isomerization of allyloxy- and homoallyloxyboranes. A one-pot isomerization/cross-aldol sequence provides aldehyde-aldehyde adducts in good yield with syn select
Rhodium-catalyzed cross-aldol reaction: In situ aldehyde-enolate formation from allyloxyboranes and primary allylic alcohols
Lin, Luqing,Yamamoto, Kumiko,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 10275 - 10279 (2013/01/15)
Dip in! A Rh/dippf catalyst generates aldehyde-derived enol boranes at ambient temperature by isomerization of allyloxy- and homoallyloxyboranes. A one-pot isomerization/cross-aldol sequence provides aldehyde-aldehyde adducts in good yield with syn select
Study of the lanthanide-catalyzed, aqueous, asymmetric Mukaiyama aldol reaction
Mei, Yujiang,Averill, Derek J.,Allen, Matthew J.
scheme or table, p. 5624 - 5632 (2012/09/05)
The development of efficient methods for the asymmetric Mukaiyama aldol reaction in aqueous solution has received great attention. We have developed a new series of chiral lanthanide-containing complexes that produce Mukaiyama aldol products with outstanding enantioselectivities. In this paper, we describe an optimized ligand synthesis, trends in stereoselectivity that result from changing lanthanide ions, and an exploration of substrate scope that includes aromatic and aliphatic aldehydes and silyl enol ethers derived from aromatic and aliphatic ketones.
A new class of ligands for aqueous, lanthanide-catalyzed, enantioselective Mukaiyama aldol reactions
Mei, Yujiang,Dissanayake, Prabani,Allen, Matthew J.
supporting information; experimental part, p. 12871 - 12873 (2010/11/16)
The development of aqueous methods for generating enantiopure β-hydroxy carbonyl compounds is an important goal because these subunits compose many bioactive compounds and the ability to synthesize these groups in water has environmental and cost benefits. In this communication, we report a new class of ligands for aqueous, lanthanide-catalyzed, asymmetric Mukaiyama aldol reactions for the synthesis of chiral β-hydroxy ketones. Furthermore, we have used luminescence-decay measurements to unveil mechanistic information regarding the catalytic reaction via changes in water-coordination number. The precatalysts presented here yielded β-hydroxy carbonyls from aliphatic and aryl substrates with outstanding syn:anti ratios and enantiometric excesses of up to 49:1 and 97%, respectively.
