Cleave and capture chemistry illustrated through bimetallic-induced fragmentation of tetrahydrofuran

The cleavage of ethers is commonly encountered in organometallic chemistry though rarely studied in the context of newly emerging bimetallic reagents. Recently it was reported that a bimetallic sodium-zinc base can deprotonate cyclic tetrahydrofuran (THF) under mild conditions without opening its heterocyclic (OC4) ring. In marked contrast to this synergic sedation, herein we show that switching to more reactive sodium-magnesium or sodium-manganese bases promotes cleavage of at least six bonds in THF, but the ring fragments are uniquely captured in separate crystalline complexes. Oxide fragments occupy guest positions in bimetallic inverse crown ethers and C4 fragments ultimately appear in bimetallated butadiene molecules. These results demonstrate the special synergic reactivity that can be executed by bimetallic reagents, including the ability to capture and control and thereby study reactive fragments from sensitive substrates.