Synthesis, Optical Resolution And Chiral Recognition Research Of Inherently Chiral Calix[4] Crown In Partial Cone

Inherently chiral calixarenes is a class of showing overall chiral compounds, whosechirality comes from the absence of the plane of symmetry or the inversion center byintroducing of achiral groups. We have designed and synthesized two of inherentlychiral calix[4]arene partial cone conformers I-6and II-3. Chemical resolution wereachived and research of their chiral recognition properties by1H NMR titrationexperiments, respectively.PartⅠ Research on inherently chiral calix[4]arene partial cone conformer I-6Inherently chiral calix[4]arene partial cone conformer I-6, whose three-dimensionalcalix-skeleton are convergent with a crown-4ether moiety, a carboxyl group and twopropyl groups. Chemical resolution was achieved by use of (S)-BINOL and as a chiralauxiliary.1H NMR titration data revealed that compound I-6does not have the abilityto differentiate both enantiomers of chiral amine and aminoalcohol guests. Theapproximately symmetric calix[4]arene skeleton of the partial cone conformer ispresumed to be responsible for its undesirable chiral recognition ability.PartⅡ Research on inherently chiral calix[4]arene partial cone conformer II-3Inherently chiral calix[4]arene partial cone conformer II-3, whose three-dimensionalcalix-skeleton are convergent with a methylenecarboxyl group and a propyl group, onthe basis of retaining the crown-4-ether group. Using R(+)-1-phenylethylamine as thechiral auxiliary to give a pair of optical pure diastereomers. Preliminary1H NMRtitration data revealed that racemic carboxylic acid II-3has the obvious ability toenantioselectively discriminate (1S,2R)-(+)-2-Amino-1,2-diphenylethanol.