Synthesis Of Polymer Derivatives From Binaphthol And The Polymer’s Application In Asymmetry Catalytic Hetero-Diels–Alder Reactions And Chiral Fluorescent Recognition

BINOL is a versatile chiral reagent. Its skeleton has attracted increasing attention and been widely used in asymmetric catalysis, asymmetric induced helical polymerization and chiral recognition.(1) Synthesis of polymer derivatives from binaphthol has been studied.(S)-6-formyl-2,2′-bis(methyloxymethoxyl)-1,1′-binaphthene was synthesized based on published method from the starting material(S)-BINOL, followed by the Grignard addition and oxidation by Dess-Martin-Periodinane to obtain the chial monomer(S)-6-acryloyl-2,2′-bis(methyloxymethoxyl)-1,1′-binaphthene(AcrM). The monomeric unit analogue(S)-6-propionyl-2,2′-bis(methyloxymethoxyl)-1,1′-binaphthene(U-Acr M) was synthesized by a similar way. Radical polymerization of AcrM was conducted under the initiation of AIBN in toluene to get the polymer poly[(S)-6-acryloyl-2,2′-bis(methyloxymethoxyl)-1,1′-binaphthene](P-AcrM).Another chiral monomer(S)-3-hydroxydiphenylmethyl-3′-vinyl-2,2′-dihydroxy-1,1′-binaphthene(DPVB1) was obtained by deprotection of(S)-3-hydroxydiphenylmethyl-3′-vinyl-2,2′-bis(methyloxymethoxyl)-1,1′-binaphthene(DPVB0) which was synthesized by the addition of Ph2 CO to methoxymethyl protected BINOL, formylation and then the Wittig reaction. Monomeric unit analogue of U-DPVB1 was synthesized using Pd/C-HCOONH4 reduction system. DPVB1 was polymerized under the way similar to the polymerization of AcrM. All the compounds were characterized by 1HNMR, 13 CNMR and optical rotation. Polymers were further characterized by gel permeation chromatography(GPC). The analysis of circular dichroism(CD) spectrum of all the six compounds of series AcrM and series DPVB1 indicated that the chiral monomers was asymmetric indued to obtain P-AcrM and P-DPVB1 which possess an excess of single screw-sense.(2) The polymer’s application in asymmetry catalytic hetero-Diels–Alder reactions has been studied. The application of Poly[(S)-3-hydroxydiphenylmethyl-3′-vinyl-2,2′-dihydroxy-1,1′-binaphthene] P-DPVB1 as chiral polymer ligand coordinated with Lewis acid in the catalytic symmetric hetero-Diels–Alder reaction of benzaldehyde with Danishefsky′s diene was studied, which result in a moderate good enantioselective(71% ee) of the HDA addut under the optimized reaction condition.P-DPVB1 shown better chiral induction compared to its monomer and monomer unitanalogue, it also can be recovered and reused without loss of catalytic activity.(3) Three kind of compounds: DPVB1,(S)-3-hydroxydiphenylmethyl-3′-vinyl-2,2′-dihydroxy-1,1′-binaphthene(abbreviated as DPVB2) and(S)-3-hydroxydiphenylmethyl-3′-vinyl-2,2′-dihydroxy-1,1′-binaphthene(abbreviated as DPVB3)that bearing vinyl and diphenylmethyl group were synthesized from the starting material(S)-BINOL. Their performance in enantioselective fluorescent recognition ofα-methylbenzylamine was tested. Relationship of fluorescence intensity with concentration of DPVB1-3 were found to be linearity on the level R2 = 0.993- 0.998 in dichloromethane(0.2- 1.0 × 10-5 M). 1H NMR test and fluorescence quenching study indicated that all of DPVB1-3 have the ability in the chiral recognition of chiralα-methylbenzylamine with the enantioselective factor of 1.04, 1.43, 2.04,respectively.