2D 1H and 13C NMR evidences of the [2 + 2] autodimerization of 2-benzyl-5-benzylidene cyclopentanone yielding two different diphenyl, dispiro cyclobutane derivatives.
The ene-ene [2 + 2] cycloaddition of 2-benzyl-5-benzylidenecyclopentanone proceeds smoothly and spontaneously in benzene-d6 or deuteriochloroform solution to give two different diphenyl dispiro [4.1.4.1] dodecan-4,11-diones. Detailed 1H and 13C 2DNMR spectroscopy (COSY, HMQC, HMBC) were performed in order to prove the existence in solution of two cyclobutane derivatives, one a previously described photodimer obtained by the UV irradiation of crystals of 2-benzyl-5-benzylidenecyclopentanone.
Díaz
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Instituto de Química, Universidad Nacional Autónoma de México, C. U. Coyoacán, México DF. maudiaz@servidor.unam.mx
Barrios
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Corona
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Guzmán
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A
Díaz
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Fuentes
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D002247:Carbon Isotopes; D003503:Cyclobutanes; D003517:Cyclopentanes / Q000737:chemistry*; D019281:Dimerization; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010636:Phenols; D013141:Spiro Compounds
D002247:Carbon Isotopes; D003503:Cyclobutanes; D003517:Cyclopentanes; D010636:Phenols; D013141:Spiro Compounds; D006859:Hydrogen