Racemic dissymmetric 2,2'‐dihydroxy‐9,9'‐spirobifluorene was prepared and resolved by clathrate formation with (R,R)‐(+)‐2,3‐dimethoxy‐N,N,N',N'‐tetracyclohexylsuccindiamide, giving rise to both enantiomers in very good yields. The absolute stereochemistry of the resolved material could be assigned by an X‐ray structure analysis of single crystals of the clathrate. Enantiomerically pure diols could be transformed into the corresponding ditriflates, which were then used as starting materials in different cross‐coupling procedures to provide a number of new enantiomerically pure spiro compounds bearing versatile functional groups suitable for further elaboration, as demonstrated by some examples. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

SummaryTwo new 9,9’-spirobifluorene-based bis(4-pyridines) were synthesised in enantiopure and one also in racemic form. These ligands act as concave templates and form metallosupramolecular [(dppp)2M2L2] rhombi with cis-protected [(dppp)Pd]2+ and [(dppp)Pt]2+ ions. The self-assembly process of the racemic ligand preferably occurs in a narcissistic self-recognising manner. Hence, a mixture of all three possible stereoisomers [(dppp)2M2{(R)-L}2](OTf)4, [(dppp)2M2{(S)-L}2](OTf)4, and [(dppp)2M2{(R)-L}{(S)-L}](OTf)4 was obtained in an approximate 1.5:1.5:1 ratio which corresponds to an amplification of the homochiral assemblies by a factor of approximately three as evidenced by NMR spectroscopy and mass spectrometry. The racemic homochiral assemblies could also be characterised by single crystal X-ray diffraction.

Two enantiomerically pure 9,9'-spirobifluorene-based bis(pyridine) ligands 1 and 2 were prepared to study their self-assembly behavior upon coordination to cis-protected palladium(II) ions. Whereas the sterically more demanding ligand, 2, gave rise to the expected dinuclear metallosupramolecular M2L2 rhombi, the sterically less demanding ligand, 1, acts as a template to give rise to a homochiral metallosupramolecular M4L4 catenane.

We have prepared a new bis(bipyridyl) ligand 1 based on a chiral 9,9´-spirobifluorene core in both enantiomerically pure forms. This ligand was found to undergo diastereoselective self-assembly to optically pure dinuclear coordination compounds upon coordination to copper(I) and silver(I) ions. Surprisingly, however, the resulting diastereomer was not found to be D2-symmetric which is usually found for similar bis(bidentate) ligands, but rather C2-symmetric with differently configurated metal centers.