The reaction of the diphosphide K-2[(tBuP)(4)] THF (1) with the germanium(I
V) compound (C2H5)(2)GeCl2 leads via a [4 + 1]-cyclo-condensation reaction
to 1,1-diethyl-1-germa-2,3,4,5-tetra-tert-butyl-2,3,4,5-tetraphospholane (C
2H5)(2)Ge(tBuP)(4) (2) with the 5-membered GeP4 ring system. 2 could be cha
racterized P-31 NMR spectroscopically, mass spectrometrically and by a sing
le crystal structure analysis.