Reaktive E=C(p-p)π-Systeme, VI [1] Reaktionen des Phosphaalkens F3CP=CF2 mit H-aciden Verbindungen/Reactive E = C(p-p)π-Systems, VI [1] Reactions of the Phosphaalkene F3CP = CF2 with H Acidic Compounds

The reactions o f the perfluorophosphaalkene F3CP = CF2 (1) with HX compounds proceed via addition to the PC double bond yielding either secondary phosphanes F3CP(H)CF2X (X = OH, OR, NR2, PMe2) or PX derivatives F3CP(X)CF2H (X = Cl, Br, SMe, SeMe, AsMe2). The rate of reaction with H2O is strongly pH-dependent, but only at pH > 13 the opposite direction of addition is observed. Similar results are obtained for the addition of alcohols, for which the presence of OR- results in two effects: (i) Reversion of the addition direction to yield F3CP(OR)CF2H; (ii) HF elimination from F3CP(H)CF2OR to give substituted phosphaalkenes. With strong bases HNR2, the addition is followed immediately by HF elimination producing the surprisingly stable phosphaalkenes F3CP = C(F)NR2 (R = Me, Et). Secondary phosphanes of the type F3CP(H)CF2X (X = OMe, OEt, PMe2) are found to be suitable precursors for the preparation of novel heterosubstituted derivatives of 1 by elimination of HF with NMe3. New compounds were characterized by NMR, MS, GC/MS and GC/IR measurements.