THEORETICAL AND EXPERIMENTAL-STUDY OF THE FACTORS INFLUENCING REGIOCHEMICAL AND STEREOCHEMICAL CONTROL IN THE REACTIONS OF NUCLEOPHILES WITH METAL-CARBONYL-COMPLEXES

The factors influencing the regio- and stereochemical control of react ions between phosphines and phosphites with (A) a series of tricarbony l(eta(7)-tropylium)metal cations (M = Cr, Mo, W) and (B) a series of t ricarbonyl(eta(6)-substituted arene)manganese cations (substituent = C l, Me, p-Me(2), 1,3,5-Me(3)) are examined theoretically using the inte raction determinant method of calculating interaction energies and exp erimentally using low-temperature infrared and H-1 NMR spectroscopy to identify the nature of the initial attack site in the substrate. In a ll cases the reactions are predicted to be orbitally controlled and ag reement is found between calculated site-nucleophile interaction energ ies and observed initial attack site both in terms of stereochemistry, e.g. exo ring attack is predicted correctly over endo ring attack, an d regioselectivity, e.g. P(OMe)(3) is predicted correctly to give meta l attack with the molybdenum and tungsten tropylium complexes.