Röntgenstrukturanalytische Untersuchungen von Diazadiphosphetidinen

X‐Ray Structure Analysis of Diazadiphosphetidines Various diazadiphosphetidines are synthesized by a modified Kirsanov reaction and subjected to X‐ray crystal structure analysis, the results of which show steric hindrance in the cyclohexyl‐substituted compound 4 . A comparison of its structure to that of the fluorine compound 12 shows that the steric hindrance occurs only in the case of chlorophosphoranes. During the Kirsanov reaction with aliphatic amines branched at the α‐position, a further reaction is observed if the amine is added in excess. The phosphonium salt 11 is characterized by ¹H‐, ¹³C‐ and ³¹P‐NMR‐spectra, FAB‐mass spectrum, elemental analysis and X‐ray crystal structure analysis.