Tri-£-butyl-cyclotriphosphane, Cyclotriphosphanes, Triphosphiranes, l,2-Di-^butyl-l,2-bis(trimethylsilyl)-diphosphane, CyclotetraphosphanesIn the reaction of magnesium with trimethylchlorosilane and t-butyldichlorophosphane the hitherto unknown tri-^-butyl-cyclotriphosphane, (<-BuP)3 (1), is produced besides the partially silylated phosphanes £-BuP(SiMe3)2 and (£-BuPSiMe3)2 as well as the cyclotetraphosphane (2-BuP)4. Shortly after the beginning of the reaction the amount of 1 is about 50 mole-% and decreases during the reaction time. Thermally and in solution the P3 ring compound (1) is surprisingly stable and can be isolated in a pure state by fractional distillation. (i-BuP)3 clearly differs from the oligomeric (£-BuP)4 by the lower melting point, the molar mass and by the 31 P NMR and IR spectra. The <-butyl groups in 1 are situated above and below the P3 ring plane.

Die Titelverbindung (III) wird durch Reaktion von Mg mit tert.‐Butyldichlorphosphin (I) und Trimethylchlorsilan (II) neben den partiell silylierten Phosphinen (IV) und dem Cyclotetraphosphin (V) erhalten.