- Competition between inter- and intramolecular photocycloaddition reactions of 9-substituted anthracenes
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A number of 9-[(arylmethoxy)methyl]anthracenes were prepared and their photoreactivity was studied. The intramolecular [4π+4π]cycloaddition competes with the intermolecular head-to-tail [4π+4π] cyclodimerization. The aryl substituents control the selectiv
- Cao, Derong,Gao, Chunmei,Dobis, Silvia,Meier, Herbert
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p. 1995 - 2001
(2008/02/11)
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- Rearrangement of the carbon skeleton in the intramolecular photoadduct of anthracene and benzene rings
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The effectivity of optical switching between anthracene derivatives 3a,b and their intramolecular photocycloadducts 4a,b is impaired by traces of acid. The systematic treatment of 4a,b with an increasing excess of formic acid revealed that - apart from the normal enolether cleavage 4a,b→6a,b→7a,b - a cleavage with rearrangement of the carbon skeleton can occur: 5b→6b′. The driving force is a stability enhancement of the involved carbenium ions 5b→5b′. A further increased excess of formic acid leads finally to a competitive ether cleavage in the tetrahydrofuran ring 5b→8.
- Cao, Derong,Dobis, Silvia,Schollmeyer, Dieter,Meier, Herbert
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p. 5323 - 5327
(2007/10/03)
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