Die Cyclopropylcarbinyl-Cyclobutyl-Homoallyl-Umlagerung. I. Teil. Synthese von Tricyclo[3.2.1.02,7]octan-3-ol,endo- und exo-Tricyclo[3.2.1.03,6]octan-4-ol und exo-Bicyclo[3.2.1]-oct-2-en-7-ol

Tricyclo3.2.1.0^2,7]octan-3-ol ( 1 ) and its 4-isomer 7 were obtained by hydroboration of tricyclo3.2.1.0^2,7]oct-3-ene ( 5 ). The former alcohol 1 is quantitatively converted to the isomeric alcohol exo-bicyclo3.2.1]oct-2-en-7-ol ( 3 ) by treatment with aqueous acid. Photolysis of 1-diazo-3-(cyclopent-3-enyl)-propan-2-one ( 12c ) gave a high yield of tricyclo3.2.1.0^3,6]octan-4-one ( 10a ). Reduction of the latter ketone produced a mixture of endo- and exo-tricyclo3.2.1.0^3,6]octan-4-ol 2 and 9 , respectively. Oxidation of these secondary alcohols with silver carbonate in benzene furnished a mixture of the ketone 10a and the lactone 14 of 6-hydroxy-bicyclo2.1.1]heptane-2-carboxylic acid. The latter is thought to be formed by oxydation of the hydrate of the strained ketone 10a .