
TY  - JOUR
A1  - Richards, KE 
A1  - Tillman, RW 
A1  - Wright, GJ 
T1  - Di-&#960;-methane photoisomerization of Dimethyl 9-Hydroxy- and 9-Acetoxy-9,10- dihydro-9,10-ethenoanthracene- 11,12-dicarboxylate
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1975
VL  - 28
IS  - 6
SP  - 1289
EP  - 1300
KW  - 
UR  - https://doi.org/10.1071/CH9751289 
N2  - The di-&#960;-methane photoisomerization of dimethyl 9-acetoxy- and 9- hydroxy-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate has been investigated. The 9-acetoxy compound (28) rearranges regiospecifically to give dimethyl 4b-acetoxy-4b,8b,8c,8d- tetrahydrodibenzo[a,f]cyclopropa[cd]pentalene-8b,8d-dicarhoxylate (29), i.e. a dibenzosemibullvalene. Rearrangement of the 9-hydroxy compound (16) gives one of two keto diesters (17) and (18) depending on the solvent used. The keto diesters have been shown to be indeno[1,2- alinden-9-ones epimeric at C 10 and are probably formed by further rearrangement of one of the expected hydroxydibenzosemibullvalenes (31). The regiospecific rearrangement of the 9-acetoxy and 9-hydroxy compounds (28) and (16) by alternative pathways is explained in terms of the effect of hydrogen bonding and the electronegativity of the 9- substituents upon the reaction profile. 
ER  -

