Thermal reaction of diastereomeric benzocyclobutenols. Evidence for reversible opening of 1,2-dihydrobenzocyclobutenols to hydroxy-o-xylylenes
Thermolysis of 1,2-dihydrobenzocyclobutenols 2a,b or 3a-c without solvent at 120 °C gave a 1:1 mixture of 2a-c and 3a-c together with 3-hydroxy-2,2-dimethyl-1-(o-methylphenyl)alkan-1-ones 1a-c and o-methylisobutyrophenone 5. Thermolysis of 2a or 3a under
Photochemical Reaction of 1-(o-Methylphenyl)-2,2-dimethyl 1,3-Diketones
The photochemistry of 1-(o-methylphenyl)-2,2-dimethylpropane-1,3-diones 4 has been investigated.Compounds 4a-h underwent photocyclization to give benzocyclobutenols 11a-h and naphthalenones 12a-h in hexane or methanol.Compound 4i gave the naphthalenone 12i in methanol.The product ratio 11:12 was greater in hexane than in methanol.This ratio increases with chain branching of the C-3 substituent R and with increasing size of R.Compounds 4a, b and d gave isobutyrophenones 13a, b and d along with products 11 and 12 in hexane.