Changes in the photochemistry of tropone or 2-methoxytropone on complexation with acids
Abstract
On addition of either BF3·Et2O or H2SO4 the valence photoisomerization of 2-methoxytropone (1) in CH3CN is diverted from 1-methoxy-(2) to 3-methoxybicyclo[3.2.0]hepta-3,6-dien-2-one (3) as products whereas with tropone there is a change from photodimerization to valence isomerization to give cleanly bicyclo[3.2.0]hepta-3,6-dien-2-one (5).