Regioselectivities in the di-.pi.-methane photorearrangement of 2-methylbenzonorbornadienes carrying ar-methoxy and ar-cyano substituents. The vinylmethyl effect
Control of regioselectivity in the di-.pi.-methane rearrangements. Triplet-sensitized photoisomerization of benzonorbornadienes carrying cyano substituents in the aryl and vinyl segments