Synthesis of the proton-ionizable lariat crown ether and chiral recognition of primary amines

An optically active proton-ionizable lariat crown ether derivative 2 was prepared. Host 2 displays enantiomeric selectivity toward phenylglycinol (Klarge/Ksmall=3.2) and phenylalaninol (Klarge/Ksmall=1.7). The key intermediate 1 was synthesized in two steps from commercially available binaphthol in 30% yield.