On the aromaticity and Meisenheimer rearrangement of strained heterocyclic amine, phosphine, and arsine oxides

The chemistry of parent phosphiranide in the coordination sphere of tungsten

2-Chloroethylphosphine W(CO)5 complex readily reacts with sodium hydride. With one equivalent of NaH, the parent phosphirane complex is obtained. With more than two equivalents, the phosphiranide complex is exclusively formed. With 1.5 equivalents, a 1 : 1 mixture of and is obtained but readily attacks at the phosphorus atom by splitting of ethylene and by the formation of the P-P complex . In turn, the P-P bond of is split by NaH to yield the phosphide complex . The phosphiranide complex is a good source for a large variety of functional phosphirane complexes . With BrCN, the 1-cyanophosphirane complex is formed. Upon heating it loses its complexing group. Upon hydrolysis, it gives the 1-hydroxyphosphirane complex which dimerizes in basic medium by opening one P-C bond of the ring to give . The reaction of with PhPCl2 yields the triphosphorus complex whose molecular structure has been established by X-ray crystal structure analysis.

On the 1,3-dipolar cycloaddition reactions of indenone with N-N-C dipoles: density functional theory calculations

Density functional theory (DFT) calculations at the B3LYP/6-311G* theoretical level have been performed to study the 1,3-dipolar cycloaddition (1,3-DC) reactions between indenone (1) and different 1,3-dipoles (diazomethane and N-methyl C-methoxy carbonyl nitrilimine, compounds 2 and 3, respectively). The geometrical and energetic properties were analysed for the different reactives, transition states and cycloadducts formed (compounds 4-11). The reactions proceed in the gas-phase by an asynchronous concerted mechanism, yielding different regiochemistry dependent on the 1,3-dipole chosen, although with dipole 3 some degree of synchrony was found in the formation of cycloadduct 5. The 1,3-DC between 1 and 3 was regioselective, being the cycloadduct 11 favoured against 9. The NMR chemical shift parameters (GIAO method) were also calculated for the reactives and cycloadducts.