Transition Metal Cation Salts in Organic Synthesis

Abstract

AbstractReaction of lithium diisopropylamide (LDA) with (η4‐1,3‐cyclohexadiene)Fe(CO)3 complexes bearing functionalized side chains at C‐5, under an atmosphere of carbon monoxide, gives bridged bicyclo[3,2,1]octene and bicyclo[3,3,1]nonene systems after electrophilic quenching. Under the same reaction conditions, intramolecular cyclization of acyclic (η4‐ 1,3‐butadiene)Fe(CO)3 complexes with functionalized side chains at the terminal position of the diene ligands furnishes fused bicyclo[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 (η7‐cycloheptatrienyl)Cr(CO) gives (η6‐cyclohepta‐1,3,5‐triene)Cr(CO)3 complexes with a functionalized 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 derivatives. The addition of a variety of the highly functionalized zinc‐copper reagents RCu(CN)Znl to the (η4‐cyclohexa‐1,3‐diene)Mo(CO)2(Cp) at the terminus of the coordinated diene ligand gives [Mo(π‐allyl)(CO)2(Cp)](Cp = cyclopentadienyl) complexes with the functionalized side‐chain at the C‐4 position of the ring. Intramolecular cyclization of the (π‐allyl)molybdenum complex containing a pendant propanoic acid unit generates the δ‐lactone derivative.