Synthesis, Structure, and Reactivity of Tetrakis( O,O ‐phosphorus)‐Bridged Calix[4]resorcinols and Their Derivatives

The synthesis and characterisation of the reactive tetrakis (O,O‐phosphorus)‐Bridged calix[ 4 ]resorcinols 3 and 4 is described. Because of its poor solubility in common organic solvents, a solid‐state NMR investigation of 3 ( 1 H, 13 C, 31 P) was conducted. Reaction of 3 with MeMgl, Me 3 SiMNe 2 , and HNMe 2 furnished the η 3 γ 3 P‐substituted cavitands 5 and 6 . Oxidative addition reactions of 6 with the (H 2 N) 2 C(=O)/H 2 O 2 (1:1) adduct, tetrachloro‐o‐benzoquinone (TOB), and hexafluoroacetone (HFA) led to the η 4 γ 5 P derivative 7 , and to the η 5 γ 5 P derivatives 8 and 9 . An X‐ray crystal‐structure determination of the tetrakis(O,O‐phosphorus)‐bridged calix[4]resorcinol 4 has been conduced. The framework displays the cone conformation; the chlorine atoms are directed inwards.