Nucleophilicities of Cyclic α‐Diazo Carbonyl Compounds. Issue 10 (13th February 2023)

• Record Type: Journal Article
• Authors: Li, Le; Hsu, Jer‐Ray; Zhao, Hongqing; Ofial, Armin R.
• Is Part Of: European journal of organic chemistry. Volume 26:Issue 10(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-02-13
• Subjects: azo compounds -- heterocycles -- kinetics -- rearrangements -- (3+2)-cycloadditions; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202300005
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: The one‐bond nucleophilic reactivities of seven cyclic α‐diazo carbonyl compounds in dichloromethane were determined by analyzing the kinetics of their reactions with benzhydrylium ions (one‐bond reference electrophiles) at 20 °C according to the Mayr‐Patz equation. Though not calibrated for pericyclic reactions, the identified nucleophilicities also reflect relative reactivities of the α‐diazo carbonyl compounds in 1, 3‐dipolar cycloadditions with dimethyl acetylenedicarboxylate. These (3+2)‐cycloadditions primarily gave spirocyclic 3 H ‐pyrazoles, which underwent thermal [1, 5]‐sigmatropic (van Alphen‐Hüttel) rearrangements to furnish 1 H ‐pyrazole‐fused tricyclic products. Abstract : The kinetics of the reactions of cyclic α‐diazo carbonyl compounds with electrophilic benzhydrylium ions were evaluated to determine the Mayr reactivity descriptors N (and s N ) of the nucleophiles. Interestingly, the thus obtained N scale also reflects relative reactivities of the diazo compounds in 1, 3‐dipolar cycloadditions with dimethyl acetylenedicarboxylate.