A Bis(heptafulvenyl)-dicyanoethylene Thermoswitch with Two Sites for Ring Closure

作者：Broman Soren Lindbaek; Petersen Anne Ugleholdt; Tortzen Christian Gregers; Vibenholt Johan; Bond Andrew D; Nielsen Mogens Brondsted^*

来源：Organic Letters, 2012, 14(1): 318-321.

DOI：10.1021/ol2030586

Suitably functionalized vinylheptafulvenes (VHFs) act as thermoswitches undergoing ring closure to the corresponding dihydroazulenes (DHAs). Here we present the synthesis of a new such thermoswitch Incorporating two heptafulvene rings on a dicyanoethylene unit. The synthetic protocol explores both the tropylium species as an electrophile and as a leaving group in the generation of the heptafulvene units. The thermally induced ring closure was enhanced as a result of two accessible sites for the reaction to occur.

• 出版日期2012-1-6