European Journal of Organic Chemistry

The kinetics of the reactions of the anions of ethyl arylacetates with quinone methides and diethyl benzylidenemalonates were investigated in DMSO solution. The resulting rate constants follow the linear free-energy relationship lg k₂ = s_N(N + E), which allowed us to derive their reactivity parameters N and s_N.

Treatment of arylphosphorus acid amides with alkali metal solutions in liquid ammonia results in dearomatisation of the arene fragments and formation of (cyclohexa-1,4-dien-3-yl)phosphorus acid amides. Diarylphosphinic amides tend to undergo Birch reduction of two arene fragments to form bis(cyclohexadienyl)phosphinic amides.

The ring-opening alkynylation of cyclopropenones with terminal alkynes is catalyzed by palladium–N-heterocyclic carbene (NHC) complexes to provide alkenyl alkynyl ketones. In contrast, [3+2] annulation to give cyclopentenones occurs if secondary propargylic esters bearing an aryl or alkenyl substituent are used.

The nucleophilic substitution of a 3,5-dichloro-BODIPY derivative with several polyazamacrocycles was investigated. By controlling the BODIPY/macrocycle ratio, some monomeric and dimeric species could be obtained. The photophysical properties of the compounds were studied as was the influence of different cations for one system.

The zwitterionic aza-Claisen rearrangement of optially active N-allylpyrrolidines and α-phenoxyacetyl fluorides proceeds with complete internal and complete 1,2-asymmetric induction to generate a new C–C bond adjacent to a chiral C-N-Boc functionality. The resulting γ,δ-unsaturated amides serve as key chiral intermediates for the total synthesis of pyrrolizidine alkaloid derivatives.