Different Rearrangement Behaviour of the Cation or Anion Derived from the Diels-Alder Adduct of 9-Ferrocenylanthracene and 1,4-Benzoquinone: Ring-Opening or Paddlewheel Formation

作者：Nikitin Kirill^*; Mueller Bunz Helge; Ortin Yannick; McGlinchey Michael J

来源：Chemistry - A European Journal, 2011, 17(50): 14241-14247.

DOI：10.1002/chem.201101854

• anions
• cations
• Diels-Alder
• rearrangement
• tautomerism

Prototropic rearrangement of the Diels-Alder adduct (3a) of 9-ferrocenylanthracene and 1,4-benzoquinone potentially furnishes 9-ferrocenyl-1,4-dihydroxytriptycene (3b) incorporating a C-2v symmetrical paddlewheel moiety. However, reaction of 3a with HBF4 unexpectedly yields instead 9-ferrocenyl10-(2,5-dihydroxyphenyl)anthracene (4) via cleavage of the C9-C12 bond to generate initially a ferrocenyl-stabilized cation. Treatment of 3a with sodium hydride and iodomethane yields 1,4-dimethoxy-9-ferrocenyltriptycene (3c) in high yield but, surprisingly, also leads to fission of the C9-C12 bond resulting, after methylation, in the formation of 9-hydroxy-9-ferrocenyl-10-(2-hydroxy-5-methoxyphenyl) dihydroanthracene (12), which readily dehydrates on silica to form 9-ferrocenyl-10-(2-hydroxy-5-methoxyphenyl) anthracene (8). The X-ray crystal structures of 3a, 3c and 4 are reported.

• 出版日期2011-12