33813-33-1Relevant academic research and scientific papers
Size-Driven Inversion of Selectivity in Esterification Reactions: Secondary Beat Primary Alcohols
Mayr, Stefanie,Marin-Luna, Marta,Zipse, Hendrik
, p. 3456 - 3489 (2021/03/01)
Relative rates for the Lewis base-mediated acylation of secondary and primary alcohols carrying large aromatic side chains with anhydrides differing in size and electronic structure have been measured. While primary alcohols react faster than secondary ones in transformations with monosubstituted benzoic anhydride derivatives, relative reactivities are inverted in reactions with sterically biased 1-naphthyl anhydrides. Further analysis of reaction rates shows that increasing substrate size leads to an actual acceleration of the acylation process, the effect being larger for secondary as compared to primary alcohols. Computational results indicate that acylation rates are guided by noncovalent interactions (NCIs) between the catalyst ring system and the DED substituents in the alcohol and anhydride reactants. Thereby stronger NCIs are formed for secondary alcohols than for primary alcohols.
Size-Induced Inversion of Selectivity in the Acylation of 1,2-Diols
Mayr, Stefanie,Zipse, Hendrik
supporting information, p. 18084 - 18092 (2021/12/02)
Relative rates for the Lewis base-catalyzed acylation of aryl-substituted 1,2-diols with anhydrides differing in size have been determined by turnover-limited competition experiments and absolute kinetics measurements. Depending on the structure of the anhydride reagent, the secondary hydroxyl group of the 1,2-diol reacts faster than the primary one. This preference towards the secondary hydroxyl group is boosted in the second acylation step from the monoesters to the diester through size and additional steric effects. In absolute terms the first acylation step is found to be up to 35 times faster than the second one for the primary alcohols due to neighboring group effects.
PPh3/Selectfluor-Mediated Transformation of Carboxylic Acids into Acid Anhydrides and Acyl Fluorides and Its Application in Amide and Ester Synthesis
Yang, Zhen,Chen, Siwei,Yang, Fang,Zhang, Chenxi,Dou, You,Zhou, Qiuju,Yan, Yizhe,Tang, Lin
, p. 5998 - 6002 (2019/08/21)
By taking the advantage of PPh3/Selectfluor system, carboxylic acids are efficiently converted into the pivotal intermediates acyloxyphosphonium ions that can selectively react with a second carboxylic acid or fluoride to in situ yield the corresponding acid anhydrides or acyl fluorides. The developed protocol features commercially availabile reagents, no involvement of base, room temperature conditions, and simple experimental procedure. Additionally, various amides or esters are readily achieved, respectively, with the addition of amines or alcohols.
Reactions of Carboxylic Acid Derivatives with Superoxide
Forrester, Alexander R.,Purushotham, Vemeshetti
, p. 945 - 951 (2007/10/02)
The mechanisms of the reactions of superoxide with carboxylic esters, acyl peroxides, and the acyl chlorides of α- and β-bromocarboxylic acids have been investigated.Experimental evidence is presented supporting the view that (a) conversion of an ester into its carboxylic acid does not proceed via the corresponding acyl peroxide; (b) conversion of acyl peroxide into carboxylic acid by superoxide involves either electron transfer to or an SN2 reaction on the peroxidic group; (c) α-bromoacyl chlorides with superoxide give the corresponding aldehyde via a cyclic peroxidic intermediate.
