Tungsten (<i>Z</i>)-1,2-Diphosphite−Alkene and (<i>E</i>)-Vinyl−Phosphite Complexes from Phosphite Fischer Carbene Complexes

Pentacarbonyl acyl tungstates <b>1</b> react with 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane to give phosphite Fischer carbene complexes <b>2</b>, which in very mild conditions readily lead to the corresponding tungsten (<i>Z</i>)-1,2-diphosphite−alkene tetracarbonyl complexes <b>3</b> via a dimerization process (R = aryl) or tungsten (<i>E</i>)-vinyl−phosphite pentacarbonyl complexes <b>4</b> via a 1,2-hydrogen shift (R = alkyl), respectively.