REGIOSELECTIVE SUBSTITUTION-REACTIONS OF SULFUR(VI)-NITROGEN-PHOSPHORUS RINGS - REACTIONS OF THE HALOGENATED CYCLIC THIONYLPHOSPHAZENES [NSOX(NPCL2)(2)] (X=CL OR F) WITH OXYGEN-BASED NUCLEOPHILES

The reactions of the cyclic thionylphosphazenes [NSOX(NPCl2)(2)] (1, X = Cl; 2, X = F) with three oxygen-based nucleophiles of increasing ba sicity, sodium phenoxide (NaOPh), sodium trifluoroethoxide (NaOCH2CF3) , and sodium butoxide (NaOBu) have been studied. The reaction of 1 and 2 with 4 equiv of NaOPh at 25 degrees C yielded the regioselectively tetrasubstituted species [NSOX{NP(OPh)(2)}2] (5d, X = Cl; 6d, X = F). Further reaction of 5d with an additional 2 equiv of NaOPh over severa l days or at elevated temperatures gave the fully substituted compound [NSO(OPh){NP(OPh)(2)}2] (5e), whereas 6d did not react further. The r eaction of 1 and 2 with 5 equiv of NaOCH2CF3 yielded in both cases [NS O(OCH2CF3){NP(OCH2CF3)(2)}(2)] (7e), and similarly reaction with 5 equ iv of NaOBu yielded [NSO(OBu){NP(OBu)(2)}(2)] (9e). In all cases, the reactions were monitored by P-31 NMR and (where applicable) F-19 NMR a nd were found to involve complete substitution at phosphorus via a pre dominantly vicinal pathway, followed by substitution at sulfur. Substi tutional control of the reactions of NaOPh, NaOBu, with 1 and 2 was fo und to conform to the following general order of reactivity, PCl2 > PC l(OR) > SOX )X = Cl, F). Although the reaction with NaOCH2CF3 followed the same order of reactivity, a significant enhancement of reaction r ate was detected with each equivalent of trifluoroethoxide added, Reac tion of 7e with excess NaOCH2CF3 led to elimination of (CF3CH2)(2)O an d the formation of the salts Na[NSO(OCH2CF3>NP(OCH2CF3)(2)NP(OCH2CF3)0 ] (11) and Na[NS(O)O{NP(OCH2CF3)2}(2)] (12). Crystals of 6d are tricli nic, space group P (1) over bar, with a = 9.789(3) Angstrom, b = 11.39 3(4) Angstrom, c 12.079(5) Angstrom, alpha 107.40(3)degrees, beta = 91 .23(3)degrees, gamma = 93.18(3), V = 1283.6(8) Angstrom(3), and Z = 2. Crystals of 5e are monoclinic, space group C2/c, with a 32.457(3) Ang strom, b = 10.747(1) Angstrom, c 18.294(2) Angstrom, beta 110.37(1)deg rees, V = 5982.4(9) Angstrom(3), and Z = 8.