Stereoselective synthesis of 9-cis-retinoic acid by Suzuki reaction

Article abstract of DOI:10.1016/S0040-4039(99)01755-4

The entire polyenic side chain of ethyl 9-cis-retinoate (7) has been stereoselectively synthesized and attached to the hydrophobic ring by a high-yielding thallium-accelerated Suzuki cross-coupling reaction. The Suzuki reaction partners, tetraenyl iodide 18 and alkenyl organoborane 19, are more conveniently used immediately after generation from their precursors. Alternative approaches using either the Stille reaction or a Suzuki reaction with a shorter polyenic component proved less efficient. The highly convergent sequence can be adapted to the preparation of analogs of 9-cis-retinoic acid (2), the natural ligand for the retinoid X (RXR) subfamily of nuclear receptors.