INTERACTION OF AN ALLENE WITH POLYVALENT IODINE DERIVATIVES - PREPARATION, X-RAY MOLECULAR-STRUCTURE, AND SOME REACTIONS OF PHENYL(2,2-DIMETHYL-4-(DIETHYLPHOSPHONO)-2,5-DIHYDRO-3-FURYL)IODONIUM SALTS

Allene 1 reacts with PhIO/BF3.Et2O or PhIF2/BF3.Et2O in CH2Cl2 at -60-degrees-C with the formation of novel phenyldihydrofuryliodonium salts 2. Molecular structures for both products 2a,b are determined by X-ray analysis. Iodonium perchlorate 2b reacts with the anionic nucleophiles (NaN3, NaOCH3, NaOC2H5, CuI/KI) to give the corresponding products of the vinylic nucleophilic substitution (6a-e) of the iodobenzene moiety. However, analogous reaction of 2b with Ph3P gives an unexpected iodide 6e as the major product, along with the usual product of nucleophilic substitution (6d). This result is rationalized by a nucleophilic attack of Ph3P on the iodine atom of the iodonium salt 2b followed by two alternative paths for subsequent ligand coupling.