Selective Bromocyclization of 2-Geranylphenols Promoted by Phosphite-Urea Cooperative Catalysts

Yasuhiro Sawamura, Hidefumi Nakatsuji, Matsujiro Akakura, Akira Sakakura,* Kazuaki Ishihara* 
Chirality2014, 26 (7), 356–360.  (Published online: 07 Feb 2014) 
DOI: 10.1002/chir.22297 

Nucleophilic phosphite-urea cooperative catalysts are highly efficient for the bromonium-induced cyclization of 2-geranylphenols.  Phosphite-N,N’-dimethylurea catalysts also show moderate activity, probably due to the steric effect of their bent conformation.