P. Yates, G. Langford
Jan 15, 1981
Citations
0
Influential Citations
12
Citations
Journal
Canadian Journal of Chemistry
Abstract
1-Methoxy-2-methyl-1,4-cyclohexadiene (3), 2-methoxy-1-methyl-1,3-cyclohexadiene (2), and 2-methoxy-1,5,5-trimethyl-1,3-cyclohexadiene (14) on heating with maleic anhydride give 1-methoxy-endo-7-methylbicyclo[2.2.2]oct-5-ene-syn-2,3-dicarboxylic acid anhydride (7) and its 6-methoxy-1-methyl (16a) and 6-methoxy-1,8,8-trimethyl (16b) analogues, respectively. On hydrolysis 16a and 16b give the corresponding keto dicarboxylic acids, 18a and 18b, via keto anhydrides 17a and 17b. Treatment of 18b with lead tetraacetate gives 1,8,8-trimethylbicyclo[2.2.2]oct-5-en-2-one (19) together with products in which rearrangement to a bicyclo[3.2.1]octane system has occurred. Treatment of 17b with bis(triphenylphosphino)nickel dicarbonyl gives only 19; similar treatment of 17a gives 1-methylbicyclo[2.2.2]oct-5-en-2-one (1). Reaction of bicyclo[2.2.2]octane-2,3-dione (27) with methyllithium gives 3-hydroxy-3-methylbicyclo[2.2.2]octan-2-one (28), its dimer 31, and a diol 30. Treatment of 5-exo-acetoxy-1, 5-endo-dimethyl-6-ox...