104941-35-7Relevant articles and documents
α- And β-Functionalized Ketones from 1,3-Dienes and Aldehydes: Control of Regio- And Enantioselectivity in Hydroacylation of 1,3-Dienes
Parsutkar, Mahesh M.,Rajanbabu
supporting information, p. 12825 - 12835 (2021/08/30)
Ketones are among the most widely used intermediates in organic synthesis, and their synthesis from inexpensive feedstocks could be quite impactful. Regio- and enantioselective hydroacylation reactions of dienes provide facile entry into useful ketone-bearing chiral motifs with an additional latent functionality (alkene) suitable for further elaboration. Three classes of dienes, 2- or 4-monosubstituted and 2,4-disubstituted 1,3-dienes, undergo cobalt(I)-catalyzed regio- and enantioselective hydroacylation, giving products with high enantiomeric ratios (er). These reactions are highly dependent on the ligands, and we have identified the most useful ligands and reaction conditions for each class of dienes. 2-Substituted and 2,4-disubstituted dienes predominantly undergo 1,2-addition, whereas 4-substituted terminal dienes give highly enantioselective 4,1- or 4,3-hydroacylation depending on the aldehyde, aliphatic aldehydes giving 4,1-addition and aromatic aldehydes giving 4,3-addition. Included among the substrates are feedstock dienes, isoprene (US$1.4/kg) and myrcene (US$129/kg), and several common aldehydes. We propose an oxidative dimerization mechanism that involves a Co(I)/Co(III) redox cycle that appears to be initiated by a cationic Co(I) intermediate. Studies of reactions using isolated neutral and cationic Co(I) complexes confirm the critical role of the cationic intermediates in these reactions. Enantioselective 1,2-hydroacylation of 2-trimethylsiloxy-1,3-diene reveals a hitherto undisclosed route to chiral siloxy-protected aldols. Finally, facile syntheses of the anti-inflammatory drug (S)-Flobufen (2 steps, 92% yield, >99:1 er) and the food additive (S)-Dihydrotagetone (1 step, 83% yield; 96:4 er) from isoprene illustrate the power of this method for the preparation of commercially relevant compounds.
Nickel(0)-Catalyzed Hydroalkylation of 1,3-Dienes with Simple Ketones
Cheng, Lei,Li, Ming-Ming,Xiao, Li-Jun,Xie, Jian-Hua,Zhou, Qi-Lin
supporting information, p. 11627 - 11630 (2018/09/21)
We developed a highly regioselective addition of 1,3-dienes with simple ketones by nickel-hydride catalyst bearing DTBM-SegPhos ligand. A wide range of aromatic and aliphatic ketones directly coupled with 1,3-dienes, providing synthetically useful γ,δ-unsaturated ketones in high yield and regioselectivity. The asymmetric version of the reaction was also realized in high enantioselectivity by using novel chiral ligand DTBM-HO-BIPHEP. The utility of this hydroalkylation was demonstrated by facile product modification and enantioselective synthesis of (R)-flobufen.
4-(2',4'-DIFLUOROBIPHENYL-4-YL)-2-METHYL-4-OXOBUTANOIC ACID AND ITS DERIVATIVES
Kuchar, Miroslav,Poppova, Marie,Zunova, Hana,Knezova, Eva,Vosatka, Vaclav,Prihoda, Marek
, p. 2705 - 2713 (2007/10/02)
Friedel-Crafts reaction of itaconic anhydride (III) with 2,4-difluorobiphenyl (II) afforded unsaturated acid IV which was hydrogenated to give 4-(2',4'-difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acod (I).A series of functional derivatives and salts of the acid I has been prepared.The antiinflammatory effect of these compounds was compared with that of acid I using selected experimental inflammation models.The analgesic activity in the intraperitoneal iritation test was also evaluated.In the case of (R)-(+)-1-phenylethylamide Vf the ratio of the diastereisomers was determined by HPLC.