Photorearrangement of 2-cyanobicyclo[2.2.1]hept-2-ene. Observation of 1,2- and 1,3-sigmatropic shifts

Irradiation of 2-cyanobicyclo[2.2.1]hept-2-ene (2-cyanonorbornene, 4 ) in hexane, with the full arc of a mercury vapour lamp, gives the rearrangement products 1-cyanobicyclo[4.1.0]hept-2-ene 5 and 7-cyanotricyclo[4.1.0.0 3.7 ]heptane 6 in the ratio 20:1. These products were separated by preparative...

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Bibliographic Details
Published in:Canadian journal of chemistry 1982-07, Vol.60 (13), p.1657-1663
Main Authors: Akhtar, Ikbal A, McCullough, John J, Vaitekunas, Susan, Faggiani, Romolo, Lock, Colin J. L
Format: Article
Language:eng ; fre
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Summary:Irradiation of 2-cyanobicyclo[2.2.1]hept-2-ene (2-cyanonorbornene, 4 ) in hexane, with the full arc of a mercury vapour lamp, gives the rearrangement products 1-cyanobicyclo[4.1.0]hept-2-ene 5 and 7-cyanotricyclo[4.1.0.0 3.7 ]heptane 6 in the ratio 20:1. These products were separated by preparative vpc. The structure of the major product 5 was determined by single crystal X-ray analysis. Reduction of 5 with lithium aluminum hydride gave the corresponding primary amine, which was converted to the p-bromobenzenesulfonamide 9 , mp 150-151 °C, which gave single crystals from ethanol-water. The crystal and molecular structures are described. The minor product 6 was hydrogenated to give 7-cyanobicyclo[2.2. 1]heptane. Formation of 5 and 6 may involve concerted σ 2s  + π 2s and σ 2a  + π 2a processes respectively, which are photochemically allowed.
ISSN:0008-4042
1480-3291
DOI:10.1139/v82-226