Design, synthesis, evaluation, and structure of vitamin D analogues with furan side chains

Article abstract of DOI:10.1002/chem.201102695

Based on the crystal structures of human vitamin D receptor (hVDR) bound to 1α,25-dihydroxy-vitamin D₃ (1,25 D) and superagonist ligands, we previously designed new superagonist ligands with a tetrahydrofuran ring at the side chain that optimize the aliphatic side-chain conformation through an entropy benefit. Following a similar strategy, four novel vitamin D analogues with aromatic furan side chains (3 a, 3 b, 4 a, 4 b) have now been developed. The triene system has been constructed by an efficient stereoselective intramolecular cyclization of an enol triflate (A-ring precursor) followed by a Suzuki-Miyaura coupling of the resulting intermediate with an alkenyl boronic ester (CD-side chain, upper fragment). The furan side chains have been constructed by gold chemistry. These analogues exhibit significant pro-differentiation effects and transactivation potency. The crystal structure of 3 a in a complex with the ligand-binding domain of hVDR revealed that the side-chain furanic ring adopts two conformations. Copyright