Binding orientation and reactivity of alkyl α,ω-dibromides in water-soluble cavitands.

Host-guest complexation of long chain α,ω-dibromides was evaluated in deep water-soluble cavitands 1 and 2. The bound dibromides (C7-C12) tumble rapidly on the NMR timescale and averaged signals were observed. The complexation allows mono hydrolysis of dibromides in aqueous solution. The arrangement of the products in the host-guest complex was fixed in an unsymmetrical manner that protects the guest from further reaction. Up to 93% yields of the mono-alcohols were obtained. The α,ω-dibromides formed a capsule with cavitand 2 and remained unreactive to hydrolysis.