Reaction of copper(II) carboxylates, Cu2(O2CR)4 (R = C(CH3)3 and CCl3) with bridging ligands, L (L = pyrazine (pyz), 4,4′-bipyridine (4,4′-bpy), and 1,4-diazabicyclo[2.2.2]octane (dabco)) gave compounds, [Cu2(O2CC(CH3)3)4L]n (L = pyz (1), 4,4′-bpy (2), and dabco (3)), [Cu2(O2CCCl3)4L2]·nH2O (L = pyz; n = 1 (4), L = 4,4′-bpy; n = 1 (5), and L = dabco; n = 3 (6)), and [Cu4(OCH3)4(O2CCCl3)4(CH3OH)2(pyz)]n·2nCH3OH (7). The X-ray structure analyses of 1 and 7 show chain structures where the carboxylate dimer units or the cubane tetranuclear units are linked by the pyrazine molecules.

The reaction of 1 -phenylallyl-lithium ( l a ) with optically active 2-halobutanes in ether in the presence of tetramethylethylenediamine or hexamethylphosphoramide gives exclusively 4-methyl-3phenylhex-I -ene (5a) (coupling at the phenyl-substituted site) with essentially 100% inversion of configuration. In contrast, treatment of 1 ,I -diphenylallyl-lithium (7 b) with (-) -2-halobutanes under the same conditions results in the formation of a mixture of 4-methyl-3,3-diphenyIhex-l -ene (5b) (coupling at C -I ) and 4-methyl-I ,I -diphenylhex-I -ene (6b) (coupling at C-3). Moreover, C-C bond formation at the I-position to provide (5b) is also found to proceed with complete inversion of configuration, while a small but significant loss of stereochemical integrity is observed in the case of the C-3 attack product (6b). These results suggest that a polar pathway should predominate for the formation of the C -I attack products (5a, b), while competition between polar and single-electron-transfer processes occurs for the formation of the C-3 attack product (6b).

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