Layered compounds. VII. Sixfold-layered cyclophane

Tetrahedron Letters No. 29, pp 2927 - 2930, 1972. Otsubo, Zensaburo Yoshiteru Printed in Crest Britain. SIXFOLD-LAYEREDCYCLOPRANR LAYEREDCOMPOUNDS. VII 01 Tetsuo Pergamon Press. Tosuka, Sakata Shigeyoshi and Soichi Misogaml, Misumi The Institute zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA of Scientific and Industrlal Research, Osaka University Sulta, (Received Aromatic a manner of suitable layered face-to-face for layers which ing effects the study of in UK for interaction // \\ El of multiple i.e., single-layered one (II), \ 12 June 1972) rings are closely bound in cyclophanes, are known as quite interaction. And the more the and quadruple-layered to exhibit benzene we will report more remarkable as p-xylene or durene), one (III), the larger doublethe the synthesis electronic of sixfold-layered interaction cyclophane and magnetic shield- // \\ GE3 I 2l/ \ rings. I- , +s 1 / layered compound (such / %I \ aromatic electronic I / publication has been observed2*3? communication, is expected bridges, the transannular e.g., triple-layered In the present (IV), by methylene increases, one (I), transannular received Japan compounds in which more than two bensenoid models number of in Japan 2 June 1972; Osaka, . Y/ ? N / Iv II 2927 2928 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA A quaternary Wa! ammonium hydroxide Pyrolysis polymers. yield of VI in boiling After based on V) was separated calcd. of 729; analysis soluble crystals characterized so, these product gave colorless for both are the nearly by 898 (ml, facts indicate soluble one (1.9%) both are of hand, the sparingly with together by treatment cm), decomp.>250°C, one; two isomers in boiling soluble as the producible of isomers quadruple-layered xylene minor one. afforded of the IR spectra 677 (s) cm-' for \ - a mixture of with an independently and VIII), and then the sparingly synthesized soluble cyclophane the previous the readily The former was assigned comparison IVa (Dz symmetry) sixfold-layered one (III)Zb’in soluble (IIIa study, major to the structure sample the the readily the /- \ /- \ / \ I/- \ /- \ /- \ *- g IVa considered of elemental of + / of VI, mol. recrystalllsatlon 8 reaction benzene. are latter. each other. q)sgeML On the Hofmann elimination with (3.7% with Satisfactory soluble and 8% compound product The NMR, IR, and W spectra the former lsomerlc soluble plates, decomp.7250”C. new compounds. same as those gave colorless On the other crystals, 673 (s) cm-' for that the readily in benzene). triple-layered compound (IV) alumina, from toluene fine from dlmethyl sixfold-layered from the sparingly the 3.7% has been obtained afforded on neutral found 737 (osmometry 1.9% one from xylene was synthesized toluene column chromatography Recrystallization wt., (VI) No. 29 IIIa IVb and IVb (Cab symmetry) IV. We have also product are encountered where the pyrolysis of VII and the sparingly (Da symmetry) by the cross-breeding isomer was assigned I to the lsomeric by direct reaction structure of VI IIIb 2929 No. 29 + /- \ (cab smetw). / \ It /- \ On analogy with III Is presumed that sixfold-layered structure In the case of cyclophane, of the readily the soluble zyxwvutsrqponml /,\ 8 Isomer Is IVa with less major sterlc IIIb crowding, whereas the sparingly solu- ble one Is IVb with more steric crowding. cH&&,oH B 1- ’ As shown In Fig. /- \ 1, the NMR spectrum of IVa reveals /- \ feature that all a striking the aromatic protons VI appear at remarkably higher due to the anisotropies of the multilayered an additivity field. Especially, cyclophanes together sandwiching bensene layers. with p-xylene Thus, as the number of to more higher indicating effect that the shielding as the number of layers field of additional of the multilayered are Included In Table layers with decreasing bensene ring cyclophanes exhibit Increases Increases, successively magnitude of the shifts, becomes less strong Bencylic ArH Inner Fig. 6t 1. NMR spectrum of sixfold-layered 7% (see Fig. 2). CH, et cyclophane (lVa> effective. bathochromic and hyperchro- I 5% There exsists the resonance positions ArH outer 41 1. of the aromatic protons depending upon the number of of the aromatic protons shift mic effects For comparison the NMIl spectra of the upper and lower bensene rings. among the chemical shifts The UV spectra two types of Inner protons are more shielded 9% In Ccl*. In particular, such zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 2930 Table 1. NMRspectra of layered cyclophanee (t value) effects in Ccl,, are prominent is varied Ar H outer bensylic inner lo. 29 as the layer up to the tripled one(I1). CH, The absorption curves of the tripled p-xylene 3.05 (s) I 3.65 (s) II 3.92 (8) 4.65 (8) IIIa 4.02 (s) 4.88 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (8) 6.7-7.9 Cm) generally and become similar in IVa 4.06 (~1 (II), log the quadrupled (IIIa), and 6.99 (s) 5.00 (s), 6.8-7.7 5.20 (s) 7.1-8.3 Cm) (ml the sixfolded shape with (IVa) become broader each other, but the E 5.0 \ ’ -*,< v, I .. ( I y,*, p,p’-dimethylbibensyl _________ 1 ___--- 11 ----- IIIa intensity per the unit in longer wavelength sas with,the IVa :. \r \ 4.0 . . . . . . . .. . . chromophore region number of increa- layers. These phenomena are attributable zyxwvutsrqponm to the increase electronic benzene 3.0 of the transannular interaction rings. information study of of among To obtain the further interaction, the emission spectra a is \ 2.0 under way. \, , I 1.0 200 Fig. 240 2. 320 280 UV spectra of layered 360 cyclophanes 400 nm in cyc lohexane References 1) T. Toyoda, 2) (a) I. T. Otsubo, (b) Tetrahedron Otsubo, T. Otsubo, S. Misogami, Letters, m, Y. Sakata and S. Misumi, Y. Sakata and S. Tsumi, Tetrahedron Letters,=, Chem. Commun.. lJ& 678 ; 4803. 3) D. T. Longone and H. S. Chow, J. Am, Chem. SOC.,~, 3898 (1964); 92, 994 (1970). 1731.