Photoisomerization of the AlEtCl2 complex of endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one

Irradiation of the AlEtCl 2 complex of endo-tricyclo[5.2.1.0 2,6 ]deca-4,8-dien-3-one (1AL) yielded the AlEtCl 2 complex of exo-tricyclo[5.3.0.0 2,6 ]deca-4,8-dien-3-one (3AL). The structure of 3, which was obtained on treatment of the irradiated solution with water, was established by its reduction to give the known exo-tricyclo[5.3.0.0 2,6 ]decan-3-one. The photoisomerization of 1AL could not be driven to completion as 3AL underwent a …