Selective reductive dimerization of homocubane series oximes

Abstract

The mixture of di- and monoethylene ketals obtained by the reaction of 1,9-dibromopentacyc lo[5.4.0.02,6.03,10.05,9]-undeca-8,11-dione followed by hydrolysis and ring contraction by Faworsky method was converted into a mixture of ethylene ketals of 7-bromopentacyclo[5.3.0.02,5.03,9.04,8]decan-6-one-4- and 5-bromopentacyclo[5.3.0.02,5.03,9.04,8]decan-6-one-8-carboxylic acid where the carboxy group was replaced by bromine along the procedure of Hunsdiecker-Borodine-Cristol. 6-Ethylene ketal of the pentacyclo[5.3.0.02,5.03,9.04,8] decan-6-one obtained by the debromination of ethylene ketals of 4,7- and 5,8-dibromopentacyclo[5.3.0.02,5.03,9.04,8] decan-6-one was hydrolyzed to ketone whose oxime was selectively reduced on a platinum catalyst into the di-6-pentacyclo[5.3.0.02,5.03,9.04,8]decylamine. The reaction of reductive dimerization was also characteristic of pentacyclo[4.3.0.02,5.03,8.04,7]-nonan-9-one and pentacyclo[6.3.0.02,6.03,10.05,9]undecan-4-one oximes, whereas the composition of the reduction products of pentacyclo[5.4.0.02,6.03,10.05,9]undecan-8-one oxime depended on the amount of the catalyst.