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.

The susceptibility of gold phosphito compounds to undergo alkyne insertion into gold–phosphorus bonds has been investigated. An electron-deficient alkyne (DMAD) underwent syn-insertion into the gold–phosphorus bond to generate a Z-vinylgold species, whereas electron-rich internal alkynes were unreactive. When a P-chiral phosphinate was used as a probe, the protodeauration and insertion steps were found to be stereospecific. In contrast to the insertion chemistry observed with DMAD, electron-deficient terminal alkynes generated alkynylgold compounds and released secondary phosphites through a reversible protodeauration process.

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