Intramolecular C–O Insertion of a Germanium(II) Salicyl Alcoholate: A Combined Experimental and Theoretical Study

The synthesis of germanium(II) 2‐ tert ‐butyl‐4‐methyl‐6‐(oxidomethyl)phenolate ( 1 ) starting from Ge[N(SiMe 3 ) 2 ] 2 and the corresponding salicyl alcohol is reported. Compound 1 undergoes an intramolecular oxidative insertion reaction of germanium into a C–O bond to result in a cyclic germanium(IV) tetraoxidogermocane ( 2 ). Addition of 3‐ tert ‐butyl‐2‐hydroxy‐5‐methylbenzyl alcohol to either compound 1 or 2 gave a spirocyclic monoorgano dioxagermine ( 3 ). The results of 1 H NMR spectroscopic studies and DFT‐D calculations are in agreement with the proposed reaction cascade in which the novel germylene 1 is first converted into the germocane 2 followed by reaction with 3‐ tert ‐butyl‐2‐hydroxy‐5‐methylbenzyl alcohol to finally provide compound 3 . Addition of 4‐(dimethylamino)pyridine to a solution of germylene 1 resulted in the formation of an air‐stable monomeric 1:1 complex ( 4 ). The characterization of compounds 1 – 4 by single‐crystal X‐ray diffraction analysis, thermal analysis, and 1 H NMR, 13 C{ 1 H} NMR, and ATR‐FTIR spectroscopy is presented.