127841-27-4Relevant academic research and scientific papers
Bioreduction of α-Acetoxymethyl Enones: Proposal for an SN2′ Mechanism Catalyzed by Enereductase
Paula, Bruno R. S.,Zampieri, Davila,Rodrigues, J. Augusto R.,Moran, Paulo J. S.
, p. 3555 - 3571 (2016/11/25)
(Z)-3-Acetoxymethyl-4-R-3-buten-2-ones (R=aryl, alkyl) and (Z)-3-methyl-4-R-3-buten-2-ones (R=aryl) were synthesized and submitted to reduction by the yeast Saccharomyces cerevisiae producing the (R)- and (S)-4-R-3-methybutan-2-ones, respectively. This stereochemistry control strategy was applied in the syntheses of (R)- and (S)-Tropional with moderate to high enantiomeric excesses. Other (Z)-3-acyloxymethyl-4-phenyl-3-buten-2-ones showed similar behavior to the (Z)-3-acetoxymethyl counterpart, and the acylated Morita–Baylis–Hillman adduct 1-acetoxy-2-methylene-1-phenylbutan-3-one produced a mixture of products, with and without the acetoxy group, via three different reaction pathways. In addition to experiments employing whole cells, those in which isolated enereductases were used suggested that the main pathway through which the loss of the acetoxy group occurs during the biocatalytic cascade is an SN2′-type reaction, rather than formal hydrogen addition followed by acetic acid elimination. Finally, related ethyl enones were reduced enantioselectively by the yeast Candida albicans, producing both (R)- and (S)-reduction products, depending on the presence of the acetoxy group in the starting material. (Figure presented.).
Expeditious and Efficient Annulation Protocol for the Synthesis of α,β-Unsaturated δ-Lactones from β-Keto Esters
Nangia, A.,Rao, P. Bheema
, p. 2375 - 2378 (2007/10/02)
β-Keto esters 6a-e are transformed into β-keto alcohols 7a-e, which are homologated to phosphonates 9a-e.Intramolecular Horner-Wadsworth-Emmons reaction affords δ-lactones 10a-d in excellent overall yields. Key words: δ-Lactones; β-Keto esters; Intramolecular; Phosphonates; Horner-Wadsworth-Emmons
Efficient synthesis of α-(hydroxymethyl) ketones not available through aldol-type processes
Hitchcock,Perron,Martin,Albizati
, p. 1059 - 1061 (2007/10/02)
An efficient synthesis of α-(hydroxymethyl) ketones from β-keto esters has been developed, which is experimentally simple, amenable to large scale production and provides products of high purity without resort to chromatography in most cases. The method is a useful alternative and complement to condensation processes.
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.
