SYNTHESIS AND TRANSFORMATION OF IRON AND TUNGSTEN COMPLEXES WITH TETRAHYDROPENTALENYL LIGANDS

New half-sandwich complexes of iron and tungsten carbonyl fragments wi th tetrahydropentalenyl ligands were synthesized, their stereochemistr y determined and several ligand transformations performed in order to demonstrate the ability of these groups to control the relative stereo chemistry of complex formation. The ligands L(1) and L(2) are derived from the diastereomerically pure (rac)-cis-1-methyl-3-phenyl-tetrahydr opentalene (1) and (rac)-1, 1-dimethyl-3-(2-methoxyphenyl)tetrahydro ( 2). The following iron complexes were synthesized: [(L(1))(CO)(2)Fe](2 ) (3), [(L(2))(CO)(2)Fe](2) (4), Na[Fe(CO)(2)(L(1))] (5), Na[Fe(CO)(2) (L(2))] (6), (L(1))(CO)(2)FeC(O)CH3 (7) and (L(2))(CO)(2)FeC(O)CH3 (8) . The following were obtained as tungsten complexes: (L(1))(CO)(3)WX [ X = H (9), Cl(10)], (L(2))(CO)(3)WH (11) and Li[W(CO)(3)(L(1))] (12). In the case of 10, one diastereoisomer could be separated; in the case of the acetyl complexes 7 and 8, both diastereoisomers have been isol ated in the pure state.