134251-11-9Relevant academic research and scientific papers
Albumin-controlled stereoselective reduction of 1,3-diketones to anti-diols
Benedetti, Fabio,Berti, Federico,Donati, Ivan,Fregonese, Massimo
, p. 828 - 829 (2002)
An unprecedented combination of high chemo- and stereoselectivity in the NaBH4 reduction of 1:1 complexes between albumin and aromatic 1,3-diketones results in the formation of anti 1,3-diols with de up to 96%.
Boron-Catalyzed Dehydrative Friedel-Crafts Alkylation of Arenes Using β-Hydroxyl Ketone as MVK Precursor
San, Htet Htet,Huang, Jie,Lei Aye, Seinn,Tang, Xiang-Ying
supporting information, p. 2386 - 2391 (2021/01/04)
Boron-catalyzed environmentally benign dehydrative Friedel-Crafts alkylation of indole/pyrrole and aniline derivatives with β-hydroxyl ketones has been developed for the first time. This method provides an efficient and green replacement of toxic and unst
Albumin-directed stereoselective reduction of 1,3-diketones and β-hydroxyketones to anti diols
Berti, Federico,Bincoletto, Simone,Donati, Ivan,Fontanive, Giampaolo,Fregonese, Massimo,Benedetti, Fabio
experimental part, p. 1987 - 1999 (2011/04/25)
The reduction of 1,3-diketones and β-hydroxyketones with NaBH 4 in aqueous acetonitrile is highly stereoselective in the presence of stoichiometric amounts of bovine or human albumin, giving anti 1,3-diols with d.e. up to 96%. The same reaction, without albumin, gives syn and anti 1,3-diols in approximately 1:1 ratio. The presence of an aromatic carbonyl group is essential for diastereoselectivity in the NaBH4/albumin reduction of both 1,3-diketones and β-hydroxyketones. Thus, 3-hydroxy-1-(p-tolyl)-1- butanone is stereoselectively reduced in the presence of albumin, while reduction of its isomer 4-(p-tolyl)-4-hydroxy-2-butanone is not stereoselective. The albumin-controlled reduction is not stereospecific as both enantiomers of 1-aryl-3-hydroxy-1-butanones are reduced to diols with identical stereoselectivities. Circular dichroism of the bound substrates confirms that aromatic ketones are recognized by the protein's IIA binding site. Binding studies also suggest that 1,3-diketones are recognized in their enol form. From the effect of pH on binding of a diketone it is concluded that, in the complex with the substrate, ionizable residues His242 and Lys199 are in the neutral and protonated forms, respectively. A homology model of BSA was obtained and docking of model substrates confirms the preference of the protein for aromatic ketones. Modelling of the complexes with the substrates also allows us to propose a mechanism for the reduction of 1,3-diketones in which the chemoselective reduction of the first (aliphatic) carbonyl is followed by the diastereoselective reduction of the second (aromatic) carbonyl. The role of albumin is thus a combination of chemo- and stereocontrol.
Chemistry of aldolate dianions. Effects of β-heteroatom substituents on ketone enolization
Van Martin,Murray, Desmond H.,Pratt, Norman E.,Zhao, Yun-Bo,Albizati, Kim F.
, p. 6965 - 6978 (2007/10/02)
β-Hydroxy ketones can be doubly deprotonated with >2 equiv of an amide base at low temperature providing both proximal or distal aldolate dianions in good to excellent yield. A variety of substitutionally biased β-hydroxy ketones give exclusively distal dianions. If the distal site is blocked, proximal dianions are formed in good yield; however, Chromatographic separation of the silylated products leads to decreased yields. Comparative enolization studies of 4-hydroxy-2-butanone, l-hydroxy-3-pentanone, and hydroxyl-substituted derivatives reveal a kinetic factor favoring proximal deprotonation of β-OTMS and β-alkoxy ketones. However, there is a thermodynamic factor favoring distal dianions that becomes significant as solutions of the dianions are warmed. Thermal stability studies indicate good room temperature stability of the dianions toward elimination and retroaldolization processes; control studies in this area also support the presence of a dianionic species. Precedent suggests that the dianions exist as internally chelated species, and we speculate that ion triplets containing bridging lithiums are good candidates for the structure of both proximal and distal dianion species. The distal dianions undergo clean reaction with aldehydes and acyl cyanides leading to β,β′-dihydroxy ketones and β-hydroxy-β′-oxo ketones, respectively.
