An anomalous intramolecular conjugate addition of N-protected imidazoles to vinyliminophosphoranes promoted by tetrabutylammonium fluoride. X-ray crystal structure of 5-ethoxycarbonyl-5-(triphenylphosphoranylidene-amino)-5,6-dihydroimida zo[2,1-a]isoquinoline

Article abstract of DOI:10.1016/0040-4020(96)00819-8

An anomalous intramolecular conjugate addition of N-SEM protected imidazoles to vinyliminophosphoranes proceeds efficiently in the presence of tetrabutylammonium fluoride (TBAF) to afford the corresponding fused imidazoles. The crystal and molecular structure of 4 have been solved by X-ray analysis. The crystal packing is governed by weak C-H···X (X = O, N or aromatic π system) hydrogen interactions because of the absence of more polarized donor groups to form hydrogen bonds.