TRANSITION-METAL CATION SALTS IN ORGANIC-SYNTHESIS

Reaction of Lithium diisopropylamide (LDA) with (eta(4)-1,3-cyclohexad iene)Fe(CO)(3) complexes bearing functionalized side chains at C-5, un der an atmosphere of carbon monoxide, gives bridged bicycle[3.2.1]octe ne and bicyclo[3.3.1]nonene systems after electrophilic quenching. Und er the same reaction conditions, intramolecular cyclization of acyclic (eta(4)-1,3-butadiene)Fe(CO)(3) complexes with functionalized side ch ains at the terminal position of the diene ligands furnishes fused bic yclo[3.3.0]octanone and bicyclo[4.3.0]nonanone derivatives after acid quenching. The addition of a variety of the highly functionalized zinc -copper reagents RCu(CN)ZnI to the (eta(7)-cycloheptatrienyl)Cr(CO)(3) gives (eta(6)-cyclohepta-1,3,5-triene)Cr(CO)(3) complexes with a func tionalized side-chain at the C-7 position of the ring. Intramolecular cyclization of ester-subsbtuted adducts using lithium diisopropylamide generates fused bicyclo[5.3.0]decane and bicyclo[5.4.0]undecane deriv atives. The addition of a variety of the highly functionalized zinc-co pper reagents RCu(CN)ZnI to the (eta(4)-cyclohexa-1,3-diene)Mo(CO)(2)( Cp) at the terminus of the coordinated diene ligand gives [Mo(pi-allyl )(CO)(2)(Cp)] (Cp = cyclopentadienyl) complexes with the functionalize d side-chain at the C-4 position of the ring. Intramolecular cyclizati on of the (pi-allyl)molybdenum complex containing a pendant propanoic acid unit generates the delta-lactone derivative.