Synthesis of Highly Symmetrical Triptycene Tetra- and Hexacarboxylates

Abstract

Two alternative procedures, both starting from easily accessible­ tetramethylanthracenes and employing the Diels-Alder addition as the key reaction step(s), have been examined in the synthesis of the title compounds.

Key words

carboxylic acids - Diels-Alder reactions - oxidations - triptycenes - arynes

References

• 1a Holý P. Závada J. Císařová I. Podlaha J. Angew. Chem. Int. Ed.  1999,  38:  381 
• 1b Holý P. Sehnal P. Tichý M. Závada J. Císařová I. Tetrahedron: Asymmetry  2003,  14:  245 
• 1c Holý P. Kováč M. Tichý M. Závada J. Buděšínský M. Císařová I. Tetrahedron: Asymmetry  2005,  16:  2031 
• 1d Holý P. Havlík M. Tichý M. Závada J. Císařová I. Collect. Czech. Chem. Commun.  2006,  71:  139 
• 3 Rybáčková M. Bělohradský M. Holý P. Pohl R. Závada J. Synthesis  2006,  2039 
• 6 Klanderman BH. Criswell TR. J. Org. Chem.  1969,  34:  3426 
• 7a Butler DN. Snow RA. Can. J. Chem.  1975,  53:  256 
• 7b Ihmels H. Schneider M. Waidelich M. Org. Lett.  2002,  4:  3247 
• 8 Hart H. Bashir-Hashemi A. Luo J. Meador MA. Tetrahedron  1986,  42:  1641 
• 9 Chan T.-L. Mak TCW. Poon C.-D. Wong HNC. Jia JH. Wang LL. Tetrahedron  1986,  42:  655. 
• 10 Hinshaw JC. Org. Prep. Proced. Int.  1972,  4:  211 
• 11 Wilcox CF. Farley EN. J. Am. Chem. Soc.  1984,  106:  7195 
• 12 Baker BR. Schaub RE. Joseph JP. McEvoy FJ. Williams JH. J. Org. Chem.  1952,  17:  149 
• 13 Skvarchenko VR. Shil’nikova AG. Zakharova G. Levina RY. Zh. Org. Khim.  1970,  6:  174 ; Chem. Abstr. 1970, 73, 3692

2

Rybáček J.; Rybáčková, M.; Høj, M.; Holý, P.; Bělohradský, M.; Kilså, K.; Nielsen, M. B., manuscript in preparation.

4

6a: ¹H NMR (400 MHz, CDCl₃): δ = 1.84 (s, 6 H), 2.35 (s, 6 H), 4.77 (s, 2 H), 6.98 (m, 2 H), 7.29 (m, 2 H), 7.42 (s, 2 H), 7.50 (s, 2 H). 6b: ¹H NMR (400 MHz, CDCl₃): δ = 1.83 (s, 6 H), 2.16 (s, 6 H), 2.34 (s, 6 H), 4.70 (s, 2 H), 7.10 (s, 2 H), 7.40 (s, 2 H), 7.46 (s, 2 H).

5

Similar problems with regioselectivity are common in aryne addition to anthracenes, cf. ref 6. Steric hindrance to aryne approach due to methyls may account well for the different outcomes obtained with anthracenes 1 and 4 in Scheme [1] .