Supramolecular photocyclodimerization of 2-hydroxyanthracene with a chiral hydrogen-bonding template, cyclodextrin and serum albuminThis article is dedicated to the warm memory of Prof. Nicholas John Turro.Electronic supplementary information (ESI) available: UV-vis spectral change of HA upon photoirradiation and HPLC, NMR and mass charts of the cyclodimers 1-4. See DOI: 10.1039/c3pp50127b

2-Hydroxyanthracene (HA) in its neutral form smoothly photocyclodimerized to four stereoisomeric [4 + 4]-cyclodimers, which were isolated and characterized for the first time, whereas the anionic form of HA turned out to be photochemically inert. Enantiodifferentiating photocyclodimerization of HA in the presence of a chiral hydrogen-bonding template (TKS159), γ-cyclodextrin (γ-CDx) and bovine serum albumin (BSA) was examined to afford chiral syn -head-to-tail and anti -head-to-head cyclodimers in modest enantiomeric excesses with TKS159 and γ-CDx, but practically no photocyclodimerization proceeded in the presence of BSA probably due to the ionization of HA in the binding sites. Supramolecular complexation and subsequent enantiodifferentiating photocyclodimerization of 2-hydroxyanthracene (HA) were examined.