Tungsten-Mediated Selective Ring Opening of Vinylcyclopropanes

The complexes TpW­(NO)­(PMe3)­(L), where L = 2H-phenol, 2H-p-cresol, 2H-5,6,7,8-tetrahydro-2-naphthol, 2H-N,N-dimethylanilinium were cyclopropanated using Simmons–Smith conditions. Cyclopropanated derivatives of 2H-N,N-dimethylanilinium were selectively ring-opened with HOTf/MeCN to form allylic species, which could be coupled with various nucleophiles. The nucleophilic addition occurs anti to the metal fragment, as determined by X-ray crystallography. Moreover, the cyclopropane ring opening occurs regioselectively, owing to the stabilization of the allylic cation by the metal fragment. The resulting ligands can, in some cases, be removed from the metal by oxidative decomplexation using ceric ammonium nitrate (CAN).