Bi(OTf)3-catalyzed 5-exo-trig cyclization via halide activation

Lewis acid activation of allyl halides utilizing Bi(OTf)3 resulted in cationic cyclization of alkenes with high efficiency. While other Lewis acids could catalyze this process with highly substituted alkenes, bismuth salts demonstrated unique reactivity in come cases. This suggested that bismuth triflate possesses interesting halophilic properties.