Nucleophilicities of Cyclic α‐Diazo Carbonyl Compounds
Le Li, J. N. C. HSU, Hongqing Zhao, Armin R. Ofial
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.
Topics & Concepts
ChemistryPericyclic reactionDiazoElectrophileSigmatropic reactionNucleophileDimethyl acetylenedicarboxylateDichloromethaneMedicinal chemistryPyrazoleComputational chemistryOrganic chemistryCycloadditionCatalysisSolventCyclopropane Reaction MechanismsOrganic Chemistry Cycloaddition ReactionsSynthesis and Catalytic Reactions