|Budget Amount *help
¥10,800,000 (Direct Cost : ¥10,800,000)
Fiscal Year 1998 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1997 : ¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1996 : ¥7,500,000 (Direct Cost : ¥7,500,000)
Bicyclo[2.2.1]hepta-2,5-diene (2,5-norbornadiene) dimerizes in the presence of a catalytic amount of Ru(1-2:5-6-η-cyclooctadiene)(1-6-η-cyclooctatriene)(Ru(cod)(cot)) and an electron-deficient olefin such as N, N-dimethylacrylamide, dimethyl fumarate or dimethyl maleate in toluene or THF to give a new compound, pentacyclo[188.8.131.52ィイD12,6ィエD1.0ィイD13,13ィエD1.0ィイD110,14ィエD1] tetradeca-4,11-diene (PCTD), in high yield along with a small amount of a known endo-endo dimer, heptacyclo[184.108.40.206ィイD12,6ィエD1.0ィイD13,13ィエD1.0ィイD14,11ィエD1.0ィイD15,9ィエD1.0ィイD110,14ィエD1]tetradecane (HCTD), which is a major product in the reaction in DMSO. Ru(cod)(cot)-dimethyl fumarate in THF was the most efficient catalyst, and the yield of PCTD was 96% even at 40℃. The structure of PCTD was directly determined by X-ray analysis of its derivative, [AgOTf(PCTD)]ィイD2nィエD2. PCTD was found to be derived via endo-endo dimerization of 2,5-norbornadiene. Formation of PCTD from two molecules of 2,5-norbornadiene involves the clea
vage of two carbon-carbon bonds. Dimerization of 7-tert-butoxy-2,5-norbornadiene gave the corresponding exo- and endo-4,9-disubstituted PCTD derivatives. Ru(cod)(cot) reacts with dimethyl fumarate to give a novel complex, Ru(cod)(dmfm)ィイD22ィエD2(dmfm=dimethyl fumarate), in high yield. The structure of the complex was also determined by X-ray analysis. At 40℃ in toluene, Ru(cod)(dmfm)ィイD22ィエD2 itself catalyzes the dimerization of 2,5-norbornadiene to give PCTD in excellent yield in the absence of olefinic additives, which enabled the large scale synthesis of PCTD (ca. 20 g). In consideration of all findings, the possible mechanisms of the formation of PCTD are discussed in detail.
To prepare various novel caged compounds, derived from PCTD, which can be expected as highly functional monomers, the following oxidation reactions of PCTD were examined. Oxidation of PCTD with hydrogen peroxide catalyzed by methyltrioxorhenium selectively gave the exo, exo-diepoxide in high yield. Osmium tetraoxide catalyzed selective syn-exo-tetrahydroxylation or syn-exo-dihydroxylation of PCTD with N-methylmorphorine N-oxide. Ruthenium trichloride-catalyzed oxidative cleavage of the olefinic groups in PCTD with sodium periodate gave a derivative of tricyclodecanecarboxylic acid with two lactone rings. Less