持田 邦夫

Radical anions of permethylated oligogermanes, Me(Me2Ge)n-Me (n=2, 3, 5, and 10), by pulse radiolysis technique showed two transient absorption bands in the UV-Vis and NIR regions. Their absorption maxima shifted to longer wavelengths with increasing the Ge-Ge chain in the permethylated oligogermanes.

Efficient synthesis of trifluoromethylated amine derivatives by use of an Et3GeNa/C6H5SCF3 combination is described. This reaction proceeded smoothly to give the desired compound in excellent yield. (C) 1997 Elsevier Science Ltd.

Polystyrene-supported organogermanium hydrides were prepared by functionalization of a polystyrene or by functionalization of a styrene followed by polymerization. The germyl groups were separated from the aromatic ring of polystyrene by methylene units in the polymeric germanium hydrides. The germanium hydrides reduced organic halides with catalyst under mild conditions in the order: C-I > C-Br > C-Cl. (C) 1997 Elsevier Science Ltd.

Et(3)GeNa/SmCl3 complex is a useful strong base for the stereoselective aldol condensation of various ketones and amides.

A new strained germacycle, 3,4-benzo-1,1,2,2-tetraethyl-1,2-digermacyclobut-3-ene (1), was prepared by treatment of 1,2-bis(chlorodiethylgermyl)benzene with sodium in toluene. At ambient temperature, 1 was gradually oxidized in air to give 3,4-benzo-1,3-digerma-2-oxaeyclopent-4-ene (2), and in the presence of sulfur, 1 was converted to 3,4-benzo-1,3-digerma-2-thiacyclopent-4-ene (3), quantitatively under similar thermal conditions. The digermacyclobutene 1 was thermally labile and readily underwent ring-opening polymerization in toluene to give the corresponding polymer 4 (M(w) = 4.4 x 10(5), M(w) = 7.4 x 10(5), M(w)/M(n) = 1.7). On thermolysis at 160 degrees C for 20 h, 1 gave two products, 4,5-benzo-1,2,3-trigennacyclopent-4-ene (5) and 3,4:6,7-dibenzo-1,2,5-trigermacyclohepta-3,6-diene (6), in reasonable yields. On the other hand, the thermolysis of 1 in the presence of phenylacetylene gave 2,3-benzo-1,4-digerma-5-phenyl-cyclohexa-2,5-diene (7), quantitatively. Further, 1 was thermolyzed in CCl4 to give two chlorinated products, 1,2-bis(chlorodiethylgermyl)benzene (9) and 1-(chlorodiethylgermyl)-2-(diethyl(trichloromethyl)germyl)benzene (10), in reasonable yields. The reaction mechanisms for the polymerization and the thermolysis are discussed.

Trimethylgermyllithium reacts with aliphatic ketones and alpha,beta-unsaturated ketones to give the corresponding trimethylgermylcarbinols stereoselectively and enolates of 3-germyl ketones regioselectively.

Laser flash photolysis of polygermanes involves both Ge-Ge bond homolysis to give polygermyl radicals and extrusion of germylenes.

Laser flash photolysis of octaisopropylcyclo-tetragermane involves both formation of hexaisopropyl-cyclotrigermane with extrusion of diisopropylgermylene and conversion to tetraisopropyldigermene. © 1992, American Chemical Society. All rights reserved.