Photocyclization of polydienes with pendant double bonds

8 Photocyclization of polydienes with pendant double bonds 

Polydienes such as 1,2-polybutadiene (3.125) 3,4-polyisoprene (3.126) 1,2-poly(trans-l,3-pentadiene) (3.127) and l,2-poly(l,4-hexadiene)s (3.128) under UV irradiation may undergo photocyclization according to the following mechanisms [795, 798, 799]  

The photocyclization reaction is accompanied by the photoinduced cis-trans-isomerization. 

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