The synthesis of P-arylated spirocyclic bisphosphonates is described. The title compounds were generated through a process that combined transesterification with a palladium catalyzed P-arylation. The cross-coupling step could be carried out at room temperature using aryl iodides, while analogous reactions involving aryl bromides required heating. Nitrogen, oxygen, and sulfur containing heterocycles were also success-fully incorporated into the framework. Using this approach 20 new arylated compounds were generated bearing a range of electrophiles and functional groups. For the more reactive aryl iodides, the catalyst loading could be decreased to 0.3 % Pd per PÀH group in scaled-up versions of the method. The two-step process does not require the use of chlorophosphorus reagents.

A spirocylic diphosphite was used to generate P-metalated bimetallic complexes through protodeauration reactions involving LAuCHBu (L = JohnPhos, BuXPhos) and metallomacrocycles through protodeauration/cyclization usingBuCHAuP^PAuCHBu precursors (P^P = flexible diphosphine). While the synthesis of the bimetallic complexes followed a stepwise process, generation of the metallomacrocycles was highly complex because of a series of reversible ligand redistribution reactions. The self-assembly was monitored, and key intermediates were identified by NMR spectroscopy and high-resolution mass spectrometry. The mechanistic investigation showed that using flexible diphosphine linkers was critical to the selective synthesis of metallomacrocycles because rigid diphosphines generated intractable mixtures of linear and cyclic compounds. The X-ray structure of a 32-membered metallomacrocycle revealed that the compound crystallized in an unsymmetrical collapsed form that was held together by two supported aurophilic interactions while the flexible diphosphines were folded along opposite sides of the metallomacrocycle. The solution structure was consistent with a symmetric species, which suggested interconversion between an open and collapsed form and/or rapid twisting of a collapsed form. The 32-membered metallomacrocycle was used to bind estrogen primarily through the formation of AuP-O···H-OR hydrogen bonds.

Transesterification of pentaerythritol (I) is followed by cross‐coupling in the presence of aryl iodides or bromides under conditions B) or C).