Beiträge zur Chemie des Phosphors, 85 Synthese und Eigenschaften der Diphosphirane (t-BuP)2CMe2 und (t-BuP)2CH2 Contributions to the Chemistry of Phosphorus, 85 Synthesis and Properties of the Diphosphiranes (t-BuP)2CMe2 and (t-BuP)2CH2

Abstract

The first three-membered P₂C heterocycles, 1,2-di-tert-butyl-3,3-dimethyl-diphosphirane, (t-BuP)₂CMe₂ (1), and 1,2-di-tert-butyl-diphosphirane, (t-BuP)₂CH₂ (2), were synthesized by [2 + 1] cyclocondensation reactions of K(t-Bu)P-P(t-Bu)K with 2,2-dichloropropane and dichloromethane, respectively. Both compounds could be isolated in a pure state by vacuum distillation. Whereas 1 is surprisingly stable under inert condi­tions, 2 dimerizes already at room temperature to form the six-membered cyclocarbaphosphane 1,2,4,5-tetra-tert-butyl-cyclo-3,6-dicarba-1,2,4,5-tetraphosphane, (t-BuP)₄(CH₂)₂ (3).The diphosphiranes 1 and 2 were characterized by elemental analysis, osmometric molecular mass determination, mass, NMR, and IR spectra. The t-butyl groups are situated on opposite sides of the P₂C ring, whereas the dimeric compound 3 possesses an “all-trans” configuration of the organyl substituents.