A Homocoupling Approach to the Key Dione of CyMe4-BTPhen - Vital Ligands for Nuclear Clean-Up by the SANEX Process

CyMe4-BTPhen and CyMe4-BTBP are the principal ligand systems used in Europe for the separation of actinides from lanthanides as a part of the SANER process for nuclear recycling and reprocessing. We present a new approach to the synthesis of the CyMe 4 fragment beginning from readily available hydroxypivalic acid. It features a cobalt-catalysed homocoupling of a neopentyl bromide to provide the key bisester precursor, thereby avoiding the requirement for technically challenging low-temperature LDA-mediated aldol chemistries.