I.~Chemistry of (eta(5):eta(5)-biphenyl)(chromium tricarbonyl)(2) dianions. II.~Two equivalent reduction of copper(I) salts. III.~A new Rieke active copper: Reduction of a copper cyanide.lithium halide complex

The dianion of the ($\eta\sp6:\eta\sp6$-biphenyl)(Cr(CO)$\sb3\rbrack\sb2$ complex reacted regioselectively with numerous electrophiles to form ($\mu$-6-alkyl-6-($\eta\sp6$-phenyl)(1-5-$\eta\sp5$)-cyclohexadienyl)) -(Cr(CO)$\sb3\rbrack\sb2$ anion intermediates. The fate of the anion intermediates included: (1) direct oxidation and formation of 2-substituted biphenyls, (2) protanation, oxidation and the isolation of 5-alkyl-5-phenyl-1,3-cyclohexadienes, (3) nucleophilic attack on the ($\eta\sp6$-phenyl)Cr(CO)$\sb3$ moiety, oxidation and formation of 2,4$\sp\prime$-disubstituted biphenyls, or (4) in the case where the initial electrophile contains an activated methylene unit, treatment with LDA, oxidation and the formation of ring annulation products. A second project involved the search for a copper anion. Reduction of CuI$\cdot$PR$\sb3$ complexes with two equivalents of lithium naphthalenide resulted in several interesting finds, most notably, as the reduction temperature of the Cu(I) salt decreased, reactivity of the copper towards oxidative addition to organic halides increased. One equivalent of alkyl or aryl bromide or chloride, reacted with one equivalent of copper after the copper was reduced at temperatures near the freezing point of THF. The CuCN$\cdot$2LiBr complex was also found to be a satisfactory source of copper. Although a copper anion was never rigorously characterized, the one equivalent reduction of CuCN$\cdot$2LiBr gave a zerovalent copper with similar reactivity to previously reported phosphine-based active copper solutions. Organocopper reagents containing ester, nitrile, and chloride functionalities were prepared and utilized in Michael reactions. The omission of phosphines allowed the ready isolation of products in high purity. The addition of allylic chlorides to the CuCN-based copper also provided a convenient method of forming allylcopper reagents. In general, allylcopper reagents are difficult to prepare since most procedures suffer from homocoupling or involve preparations which call for transmetallation steps. Functionalized allylcopper reagents containing esters, nitriles, epoxides, and chlorides, in turn, were prepared and reacted with acid chlorides, aldehydes and ketones