Abstract A series of α, ω-boryl (bromo) alkanes of the general formula R 2 B [BOND](CH 2) n [BOND] Br (n= 3, 4, 5, 6) was obtained in high yield following a standard hydroboration protocol. Upon treatment with Mg turnings and formation of the respective Grignard species, all alkanes with n= 4 to 6 underwent an unprecedented boron-centered cyclisation reaction with formation of boratacyclopentanes,-hexanes, and-heptanes, respectively. All new ...