6] Crystal data of polymeric 1 [LiC,H;O],: 1!4 = 468.22. monoclinic. space group C2:c. o = 3322(2), h = 976.7(7). c = 2491(2) pm, {! = 130.47(3) . V = 6.149(8) nm', 2 = 8. p, = 1 011 Mgm ', R000) = 2016. ; . = 0.71073 A. / I (Mo,,) = 0.066 min-I, T = 153 K. data were collected on a Sloe-Siemens-AED. Intensities of a 0.9 x 0 1 x 0.05 mni rapidly cooled crystal in an oil drop [22] were collected by the ?O:w method in the range o f 8 ' 5 20 I 45 . Of a total of5121 refections. 4028 were independent and 4024 used to refine 368 parameters, largest difference peak and hole: 223 and -1Y5enm '. RI(F>4rl(F)) = 0.079 and isR2 = 0.230 (all data) with R1 = X11FuI -I~I I~'~I 6~I and wR2 = (Cw(F: -F~)*/XUJ(F:)')"~~. The structure was solved with direct methods (SHELXS-YO [23]) and relined by fullmatrix least-squares on F2 (SHELXL-Y3 [24]). The hydrogen atom positions of the CHI groups were refined freely with the C-H bond length restrained to he the same while a riding model was applied to refine the hydrogen atom positions of the other groups. Further details of the crystal sructure investigations may he obtained from the Director of the iem. 1983. 87. 73. W. Bauer. P. von R. Schleyer in A d w n m s in Curhanii~n Ch(wiistri~. W . 1 (Ed.: V. Snieckus). JAI Press. Greenwich. CT, 1992, p. 89. LI-O,,,,,,~ bond scrambling must be rapid on the NMR time scalc. W. Bauer. F Hampcl, J Cliem. Soc. Clicm. ~' i m m i i r n 1992, 903. and references therein F. Gabriel, H r h . Chim. A r m 1983, 66. 308. A8 values of 56.6 and 57.2 have been determined for the closely related r-lithio-23dihydrofuran and a-lithio-2,3-dihydro-4H-pyran. the carbenoid characteiof which IS well established [5c]. see ref. [18] [?1] H. D. Verkruijsse, L Brandsma. P. von R. Schleyer. J Or,cpiomrt. Clirm. 1987.[22] T.

A new family of optically active cyclophane receptors for the complexation of mono-and disaccharides in competitive protic solvent mixtures is described. Macrocycles (À)-(R,R,R,R)-1 ± 4 feature preorganized binding cavities formed by four 1,1'-binaphthalene-2,2'-diyl phosphate moieties bridged in the 3,3'-positions by acetylenic or phenylacetylenic spacers. The four phosphodiester groups converge towards the binding cavity and provide efficient bidentate ionic H-bond acceptor sites (Fig. 2). Benzyloxy groups in the 7,7'-positions of the 1,1'-binaphthalene moieties ensure solubility of the nanometer-sized receptors and prevent undesirable aggregation. The construction of the macrocyclic framework of the four cyclophanes takes advantage of Pd 0 -catalyzed arylÐacetylene cross-coupling by the Sonogashira protocol, and oxidative acetylenic homo-coupling methodology (Schemes 2 and 8 ± 10). Several cleft-type receptors featuring one 1,1'-binaphthalene-2,2'-diyl phosphate moiety were also prepared (Schemes 1, 6, and 7). An undesired side reaction encountered during the synthesis of the target compounds was the formation of naptho[b]furan rings from 3-ethynylnaphthalene-2-ol derivatives, proceeding via 5-endo-dig cyclization (Schemes 3 ± 5). Computer-assisted molecular modeling indicated that the macrocycles prefer nonplanar puckered, cyclobutane-type conformations (Figs. 7 and 8). According to these calculations, receptor (À)-(R,R,R,R)-1 has, on average, a square binding site, which is complementary in size to one monosaccharide. The three other cyclophanes (À)-(R,R,R,R)-2 ± 4 feature, on average, wider rectangular cavities, providing a good fit to one disaccharide, while being too large for the complexation of one monosaccharide. This substrate selectivity was fully confirmed in 1 H-NMR binding titrations. The chiroptical properties of the cyclophanes and their nonmacrocyclic precursors were investigated by circular dichroism (CD) spectroscopy. The CD spectra of the acyclic precursors showed a large dependence from the number of 1,1'-binaphthalene moieties (Fig. 9), and those of the cyclophanes were remarkably influenced by the nature of the functional groups lining the macrocyclic cavity (Fig. 11). Profound differences were also observed between the CD spectra of linear and macrocyclic tetrakis(1,1'-binaphthalene) scaffolds, which feature very different molecular shapes (Fig. 10). In 1 H-NMR binding titrations with mono-and disaccharides (Fig. 13), concentration ranges were chosen to favor 1 : 1 hostÀguest binding. This stoichiometry was experimentally established by the curve-fitting analysis of the titration data and by Job plots. The titration data demonstrate conclusively that the strength of carbohydrate recognition is enhanced with an increasing number of bidentate ionic hostÀguest H-bonds (Table 1) in the complex formed. As a result of the formation of these highly stable H-bonds, carbohydrate complexation in competitive protic solvent mixtures becomes more favorable. Thus, cleft-type receptors (À)-(R)-7 and (À...

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