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Synthesis 2001(8): 1175-1180
DOI: 10.1055/s-2001-15064
DOI: 10.1055/s-2001-15064
PAPER
© Georg Thieme Verlag Stuttgart · New York
Regioselectivity of the Di-π-Methane Rearrangements of 1,4-Dialkoxy-9,10-bis(methoxycarbonyl)dibenzobarrelenes in Solution and in the Solid State
Weitere Informationen
Received
1 March 2001
Publikationsdatum:
24. September 2004 (online)
Publikationsverlauf
Publikationsdatum:
24. September 2004 (online)
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Abstract
Irradiation of solutions of the title compounds led to the regioselective formation of one of the two possible dibenzosemibullvalenes, as a consequence of the stabilization of intermediate biradicals by the alkoxy groups present. Continued irradiation of the reaction mixture converted the main product into a dibenzocyclooctatetraene as secondary photoproduct. Irradiation of the solid neopentoxy-substituted dibenzobarrelene afforded, almost exclusively, the dibenzosemibullvalene that is the minor photoproduct on irradiation in solution. Presumably, due to steric constraints in the crystal, the formation of the other isomer is prevented.
Key words
photochemistry - rearrangements - isomerizations - polycycles - biradicals
- 1
Zimmerman HE. In Organic Photochemistry Vol. 11:Padwa A. Marcel Dekker; New York: 1991. p.1 -
2a
Chen J.Scheffer JR.Trotter J. Tetrahedron 1992, 48: 3251 -
2b
Zimmerman HE.Sulzbach HM.Tollefson MB. J. Am. Chem. Soc. 1993, 115: 6548 -
2c
Scheffer JR.Trotter J.Gudmundsdottir A. In CRC Handbook of Organic Photochemistry and PhotobiologyHorspool WM.Song P.-S. CRC Press; Boca Raton: 1995. p.204 -
2d
Sajimon MC.Ramaiah D.Kumar SA.Rath NP.George MV. Tetrahedron 2000, 56: 5421 -
2e
Nair V.Anil kumar G.Prabhakaran J.Maliakal D.Eigendorf GK.Williard PG. J. Photochem. Photobiol., A 1997, 111: 57 - 3
Snow RA.Cottrell DM.Paquette LA. J. Am. Chem. Soc. 1977, 99: 3734 -
4a
Ihmels H. Eur. J. Org. Chem. 1999, 1595 -
4b
Ihmels H.Engels B.Faulhaber K.Lennartz C. Chem. -Eur. J. 2000, 6: 2854 -
5a
(a)See ref. 2b.
-
5b
Rattray G.Yang J.Gudmundsdottir AD.Scheffer JR. Tetrahedron Lett. 1993, 34: 35 -
6a
Bender CO.Clyne DS.Dolman D. Can. J. Chem. 1991, 69: 70 -
6b
Russel RK.Wingard RE.Paquette LA. J. Am. Chem. Soc. 1974, 96: 7483 -
6c
Zimmerman HE.Givens RS.Pagni RM. J. Am. Chem. Soc. 1968, 90: 6095 -
6d Recent summary of the thermal rearrangements:
Quast H.Heubes M.Dietz T.Witzel A.Boenke M.Roth WR. Eur. J. Org. Chem. 1999, 813 - 7
Banciu MD.Stanescu MD.Petride A.Parvulescu L.Pop M. Chem. Ber. 1993, 126: 2513 - 8
Adam W.DeLucci O.Peters K.Peters E.-M.von Schnering HG. J. Am. Chem. Soc. 1982, 104: 5747 - 9
Viehe HG.Janousek Z.Merenyi R. Acc. Chem. Res. 1985, 18: 148 -
10a
Adam W.Harrer HM.Kita F.Nau WM. Adv. Photochem. 1998, 24: 205 -
10b
Wu Y.-D.Wong C.-L.Chan KWK.Yi G.-Z.Jiang X.-K. J. Org. Chem. 1996, 60: 746 - 11
Adam W.van Barnefeld C. J. Am. Chem. Soc. 1999, 121: 10820 -
12a
Wartini AR.Staab HE.Neugebauer FA. Eur. J. Org. Chem. 1998, 1161 -
12b
Quast H.Fuchsbauer L. Chem. Ber. 1986, 119: 1016 - 13
Quast H.Schulze J. Liebigs Ann. Chem. 1990, 509 -
14a
Lepage Y. Ann. Chim. (Paris) 1959, 13: 1137 -
14b
Laatsch H. Liebigs Ann. Chem. 1980, 140