Synthesis and preparation of alkaline-earth-metal triphenylmethanides M(CPh3)2(18-crown-6)(HMPA)2 and the ether scission products [M(C12H23O6) (N(SiMe3)2)]2 (M = Sr, Ba)

The emerging organometallic chemistry of the heavy alkaline-earth metals critically requires a diverse selection of target compounds to understand the metal-ligand bond characteristics. Accordingly, we set out to prepare a new series of target compounds involving the triphenylmethanide ligand. By investigating various synthetic strategies, we found that transamination results in crown ether scission with formation of vinyl ether, whereas the use of strontium and barium dibenzyl reagents leads to the desired products in good yield and purity.