Facile synthetic route to cone-shaped phosphorylated [CH2P(O)Ph2] calix[4]arenes

Abstract

Selective incorporation of one, two or four CH₂P(O)Ph₂ substituents at specific sites in para-tert-butylcalix[4] arene was achieved using NaH and an appropriate alkylating agent; the tetrasubstituted compound (structure established by X-ray crystallography) was quantitatively reduced to the corresponding tetraphosphine L⁶ which, by reaction with [{Pd(C₆H₄CH₂NMe₂-o)Cl}₂], gave access to the tetranuclear complex [{Pd(C₆H₄CH₂NMe₂-o)Cl}₄L⁶].