Reactions of (acenaphthylene)chromium tricarbonyl with organolithium compounds, trifluoroacetic acid, and organotin hydrides

Article abstract of DOI:10.1021/om00145a004

The reactivity of (acenaphthylene)chromium tricarbonyl (I) has been studied. Lithiation at the 3-position of the ligand is facile, and the resulting species was used, in situ, in further reactions with D₂O, CH₃I, (CH₃)₃SiCl, BrCH₂CH₂Br, CH₃CHO, and C₆H₅CHO to provide derivatives of I substituted in the 3-position. Reactions of I with lithium salts of four tertiary carbanions (LiR, R = C(CH₃)₂CN, C(CH₃)₂CO₂C₂H₅, C(CH₃)₂CON(C₂H₅)₂, and C(CH₃)₃) result in addition of the carbanion to the coordinated hydrocarbon; subsequent oxidation using I₂ yields monosubstituted acenaphthylenes RC₁₂H₇ and a coupled product, R₂C₂₄H₁₂. The former product occurs as a mixture in which the 3-substituted isomer is the predominant species (>90%). Crystal structure studies on 3-C₁₂H₇C(CH₃)₂CO₂C ₂H₅ and on C₂₄H₁₂[C(CH₃)₂CON(C ₂H₅)₂]₂ are reported. Butyllithium adds to the double bond in I, and, after protonation one can isolate Cr-(CO)₃(η-1-C₄H₉C₁₂H ₇). Free radical addition of trimethyltin hydride to this double bond is also seen, forming Cr(CO)₃[η-1-(CH₃)₃SnC₁₂H ₇]. When dissolved in neat trifluoroacetic acid, I undergoes a unique oxidative coupling reaction through the hydrocarbon giving a product Cr(CO)₃(η-C₂₄H₁₈). A number of anticipated reactions of I were found not to occur.