Synthesis and Thermal Isomerization of Tricyclo1,6>dec-7-ene (Propell-7-ene) to 3,8-Dimethylenecyclooctene

Article abstract of DOI:10.1021/jo00344a019

Tricyclo<4.2.2.0^1,6>dec-7-ene (<4.2.2>propell-7-ene; 1) has been prepared from cis-4-cyclohexene-1,2-dicarboxylic anhydride through a conventioanal 12-step reaction sequence by way of bicyclo<4.2.0>oct-1(6)-ene and tricyclo<4.2.1.0^1,6>nonane-9-carboxaldehyde tosylhydrazone.It is isomerized thermally to 3,8-dimethylenecyclooctene (2) with activation parameters E_a = 35.8 +/- 1.3 kcal mol^-1 and log A = 12.6 +/- 0.6.Two possible explanations for the isomerization are considered: reaction by way of a short-lived bicyclo<4.2.2>deca-1(8),6-diene intermediate or direct cleavage of C(1)-C(6) and C(9)-C(10) simultaneously.