N-Heterocyclic carbene phosphaketene adducts as precursors to carbene–phosphinidene adducts and a rearranged π-system

Abstract

The nucleophilic attack of NHCs on the electron deficient carbon of tetryl substituted phosphaketenes Ph₃E–PCO (E = Sn–Si), leads quantitatively to the formation of NHC–phosphaketene adducts. With E = Sn or Ge, these zwitterionic adducts decompose upon thermolysis under the release of carbon monoxide to give zwitterionic NHC–phosphinidene adducts. With E = Si an OCP to CPO rearrangement occurs which leads to the formation of a linear π-conjugated molecule, NHCCP–O–SiPh₃.