[3.3.2]- and [3.3.3]Propellanes in Reactions with Oxidizing Electrophiles

The structure of [3.3.2]- and [3.3.3]propellanes, their framework analogs, and their radical-cations was investigated by computational methods (BLYP and B3LYP) in the 6-31G* basis set. The reactivity of the propellanes toward model oxidizing electrophiles does not contradict the quantum-chemical calculations. In the case of the tetracyclic framework analog of [3.3.3]propellane the reaction takes place as C—H substitution, whereas in the case of [3.3.2]propellanes it takes place as C—C-oxidative addition.     

Phosphorylated imidazo[1,2-a]pyridines

The reaction of phosphorus(III) halides with imidazo[1,2-a]pyridines in the presence of bases leads to the formation of 3-phosphorylated imidazo[1,2-a]pyridines. The reaction proceeds in high yield and requires no catalysts. In the compounds obtained, in contrast to phosphorylated indolizines, the phosphorus–heterocycle bond is stable and not cleaved by dry hydrogen chloride, alcohols, or water. Imidazo[1,2-a]pyridines with the phosphinic and phosphinous groups can be alkylated both at the phosphorus and at the nitrogen atom of the heterocycle, the alkylation direction being dependent on the strength of the alkylation reagent used. © 1995 John Wiley & Sons, Inc.