Comparison of the Electrophilic Reactivities of N‐Acylpyridinium Ions and Other Acylating Agents1. Issue 11 (20th February 2013)

• Record Type: Journal Article
• Authors: Nigst, Tobias A.; Mayr, Herbert
• Is Part Of: European journal of organic chemistry. Issue 11(2013)
• Page Start: 2155
• Page End: 2163
• Publication Date: 2013-02-20
• Subjects: Kinetics -- Linear free energy ­relationships -- Acylation -- Amines -- ­Organocatalysis; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201201540
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: The kinetics of the reactions of carbanions, carboxylate anions, and primary and secondary amines with acylating agents were studied in acetonitrile and dimethyl sulfoxide (DMSO) under first‐order conditions by UV/Vis spectrophotometry and conductimetry. Whereas reactions of a large variety of nucleophiles with ordinary carbanions and Michael acceptors generally follow the linear free energy relationship lg k 2 (20 °C) = s N ( N + E ), separate correlation lines for different types of nucleophiles were found when (lg k 2 )/ s N was plotted against N for the reactions with acyl derivatives2 –5 . Even when nucleophilic attack is rate determining, the reactivities of acylating agents towards nucleophiles cannot be described by a single set of nucleophile‐independent electrophilicity parameters. Abstract : The kinetics of the reactions of amines and carbanions with acylating agents were studied in acetonitrile and DMSO solution at 20 °C. Separate correlation lines for different types of nucleophiles were found when (lg k 2 )/ s N was plotted against the nucleophilicity parameters N for these reactions, indicating the limitation of the depicted correlation.