the cold ( - 196 “C) pyrolyzate was treated with methyl acry- late (5.4 g, 0.06 mol). The mixture was allowed to warm up to room temperature, and acetonitrile and excess methyl acry- late were removed in uacuo, yielding 4.0 g (99%) of (6), b. p. 7O0C/1O-’ torr (‘H-NMR, see [‘I).

Silver fulminate (84: Powdered (6c) (106 mg; 0.45 mmol) was heated at 100-1 10 “C for 11 h with pumping at 10 torr. The volatile products (acetonitrile and COJ were isolated in a cold-trap. The solid residue (68 mg, 100%) consisted of dangerously explosive silver fulminate (identified by IR comparsion with a sample prepared according to Nefr9’). Though no explosions have occurred during this preparation, due safety precautions should be taken.

Received- February 27, 1979: [Z 222 IE]

German version: Angew Chem. 91. 503 (1979) revised: March 23, 1979

C. Grundmann, P. Grunugert The Nitrile Oxides. Springer, Berlin 1971. refer- ences cited therein. C. Wentrup, W Reichen, Helv. Chim. Acta 59, 2615 (1976); W. Reichen, C. Wentrup, ibid. 59. 2618 (1976); C. Wenrrup, H.- W. Winter, Angew. Chem. 90, 643 (1978); Angew. Chem. Int. Ed. Engl. 17, 609 (1978): C. Wenfrup, U. Sturz. H:J. Wollweber, ibid. 90, 731 (1978) and 17, 688 (1978); C. Wenrrup, Chimia 31. 258 (1977). ( 2 ~ ) : L. Bouteaulr. A . Wahl, Ber. Dtsch. Chem. Ges. 38. 926 (1905); (2b): L. Cluisen, W. Zedel. ibid. 24, 140 (1891). a) W. Beck. P. Swoboda, K. Feldl, R. S. Tobias. Chem. Ber. 104, 533 (1971): b) cf. W. Beck. ibid. 95. 341 (1962). C. Crundmann, R. K. Bansal, P S. Osmanski, Justus Liebigs Ann. Chem. 1973, 898; C. Grundmann, G. W. Nickel, R. K . Bunsul, hid. 1975, 1029, refer- ences cited therein. R. Huisgen. M. Christ/, Chem. Ber. 106, 3291 (1973). Preliminary experiments indicate that hitherto unknown organic fulminates. RO NC. may be formed in a similar manner. Thus, flash thermolysis of the 0-benzyl and 0-phenyl derivatives of (2u) gave low yields of benzyl isocya- nate and phenyl cyanate, respectively (C. Wenrrup, B. Cerechr, D. Laquu, U . Slutr. unvublished results). Benryl cyanate would not be isolable under these , ~~

conditions, since i t already isomerizes to benzyl isocyanate at room tempera- ture (K. A . Jensen. A. Holm, J . Wulff-Jensen. Acta Chem. Scand. 23, 1568 (1969)). Phenyl cyanare rearranges to phenyl isocyanate at 900-1000°C (C. Wentrup. J.-P Hagenbuch, unpublished results).

[S] N. M . Lrin. C Wentrup, Helv. Chim. Acta 5Y, 2068 (1976). [9] J, U. Nef: JUSIUS Liebigs Ann. Chem. 280. 291 (1894).

Polycyclic Azoalkanes via Dipolar Cycloaddition of 4-Phenyl-l,2,4-triazoline-3,5-dione with Strained Bicy- clic Olefind**]

By Waldemar Adam, Ottorino De Lucchi, and Ihsan Eudenrl We required a convenient synthesis of the previously

unknown tricyclic azoalkane ( 4 ) for the generation of the corresponding diradical, which is a potential intermediate of the di-n-methane rearrangement of benzonorbornadiene

Since the highly reactive 4-phenyl-l,2,4-triazoline-3,5-dione ( I ) is known to undergo cycloaddition with strained polycyclic olefins[21, we undertook the reaction of (1 ) with the bicyclic species benzonorbornadiene (2); the cycloadduct (3) could

(2) “ I .

[*I Prof. Dr. W. Adam (NIH Career Awardee. 1975-SO), Dr. 0. De Lucchi, Dr. 1. Erden Department of Chemistry, University of Puerto Rico Rio Piedras, Puerto Rico 00931 (USA)

[**I Acknowledgments are made to the Donors of the Petroleum Research Fund (1 1022-AC-l), administered by the American Chemical Society, the National Science Foundation (CHE-78-12621), and the National Institutes of Health (GM-21 119-03, GM-00141-04, and RR-8102-06). We thank Mr. P. Herndndez, undergraduate research participant in the NIH sponsored SUBE program. lor technical assistance.

be reduced to ( 4 ) (Scheme 1). This cycloaddition could also be applied to compounds (5) - (7) .

Refluxing of stoichiometric amounts of (I ) and (2) (CHC13, 30min) led to complete decoloration of the red ( I ) . Evapora- tion of the CHC13 and column chromatography on Florisil,

Scheme 1

t

elution with CH2Cl2, and recrystallization from ethanol afforded the pure adduct ( 3 ) . Refluxing of (3) with KOH in isopropyl alcohol (90min under N2), neutralization with 3~ HCI, and treatment with CuClz in CH30H, followed by 3~ NaOH, afforded the azoalkane ( 4 ) . It was purified by sublimation (6O0C/O.2 torr) and recrystallization from hex- ane.

I 1

Similarly, refluxing a solution of stoichiometric amounts of norbornene ( 5 ) with ( I ) (CH2C12. 3 h) afforded the crude cycloadduct (81, which was purified by column chromatogra- phy on Florisil (eluant; CH2C12) and recrystallization from ethanol. This example clearly established that benzoannelation is not necessary for the reaction.

Refluxing of the olefin ( 6 ) with ( I ) in CHC13 gives the adduct ( 9 ) which was isolated by column chromatography on Florisil and recrystallization from ethanolL6]. Clearly the cycloaddition must involve dipolar species (cf. Scheme 1) since bromine addition to (6) proceeds via a similar cationic rear- rangement I3 ’.

Stirring stoichiometric amounts of (7), i. e. the oxa analogue of (2), and ( I ) (CHzC12, ca. 12h) affords the cycloadduct (10). It was purified by Florisil chromatography (CH2C12 as eluant) and recrystallization from EtOH. Physical data of all the new compounds are compiled in Table 1.

468 0 Verluy Cliemie, GmhH, 6940 Wr.inheirn, 1979 05 70- 0833/ 79/O606- 0468 $ 02. S0/0 A J I ~ ~ W . Cliem. I n r . Ed. Eityl. 18 (1979) No. 6

Table 1. Physical data of the new compounds ( 3 ) , ( 4 ) , (8)-(10). All compounds gave correct elemental analyses.

(3) : m.p. 179-180°C; yield 95%: 'H-NMR (CDCI,, TMS): 6=1.53 (d, H h t ; B part of AB system), 2.28 (d, Hh: A part of AB system), 3.75 (m, Ha, H,,), 4.61 (m, H,, Hc,), 7.15 (br. s, C6H4), 7.39 (br. s, C6H5); "C-NMR

53.43. 46.12, 34.53 (CO resonances not recorded); IR (KBr): 3020, 1785, 1715, 1500, 1412 cm- ' ( 4 ) : ni. p. 74-75°C; yield 74 %: 'H-NMR (CCI4, TMS): a= 1.20 (ni. Hbr Hb,). 2.78 (m, HJ, 3.21 (m, H,,), 4.63 (m, He), 5.26 (m, H,.I. h S S i t i i C,~ l14) : IR (CCI,): 3100, 3020, 2985, 2960, 1495, 1470. 1383, 1267, 1220 c n - '

( 8 ) : m.p. 133--134"C; yield 17%; 'H-NMR (CDCI3, TMS): 0=1.2-2.0 (m, 3Hb, 3Hb.), 2.60 (m, H,, Ha,), 4.25 (m, H,, H,,), 7.25 (m, CIHS): IR (CC14;CDCI,): 2960, 1775, 1725, 1505, 1410, 910 cm-' (9). m.p. 202-203°C; yield 31 %: 'H-NMR (CDCI,, TMS): 6=1.98 (m, 4Hd). 3.07 (m, Ha), 3.48 (1, H=,; J(H,.-HH,)=4.0Hz), 4.35 (m, ZH,), 7.0 (br. s, CbH4), 7.22 (m, C6HS); IR (CDCI,): 3080, 3060, 3040, 2960, 1770, 1705, 1600, 1500, 1400 cm- ' ( 1 0 ) ' m.p. 145--146°C: yield 60%: 'H-NMR CDCl,, TMS): 6=4.25 (m,

(m, C6H5); IR (KBr): 3040, 1790, 1710, 1600, 1495, 1400, 1320, 1260, 1230, 1150, I090 cm-'

(CDC13) 6=129.17,128.36,128.03, 127.11,125.43,124.08, 120.45, 76.84, 58.64,

Hh,), 4.35 (m, H,,), 5.22 (br. S, Hb), 5.41 (br. S , Ha), 7.08 (m, CsH,), 7.20

The reactions reported here provide a synthetic entry into azoalkanes which would be difficult to prepare by classical methods and are of interest as precursors of diradical interme- diates postulated in photochemical transformations.

Received: February 21, 1979 [Z 223 IE] German version: Angew. Chem. 91, 512 (1979)

CAS Registry numbers: (i), 4233-33-4; ( 2 ) . 4453-90-1 ; ( 3 ) , 70332-87-5; (4) . 70332-88-6: (S), 498- 66-8: (61, 24309-43-1 ; (7) , 573-57-9; (a), 70332-89-7; ( 9 ) , 70332-90-0: ( 1 O), 35261 -49-5

[I] J . R . Edman, J. Am. Chem. SOC. 91, 7103 (1969). [2] T J. Katz , N . Acton, J. Am. Cbem. Soc. 95, 2738 (1973); A. R. Browne,

L. A. Paquettr, J. Org. Chem. 43, 4522 (1978); H . E . Zimmerman, R. J . Boettcher, ,V. E. Buchler, G. E. Keck, M . G. Steinmetz, J. Am. Chem. Soc. 98, 7680 (1976); R. C. Cookson, S . S . H . Gilani, 1. D . R . Stevens, .I. Chem. Soc. C1967, 1905.

131 R P. Johnson. A. Exarchon, C. W Jefford, J. Org. Chem. 42, 3758 (1977).

tetrahedro-Tetraphosphorus as Monodentate Ligand in a Nickel@) Complex By Paolo Dapporto, Stefano Midollini, and Luigi Sacconil'l

The existence of a P4 unit was proposed in some rhodium complexes by Ginsberg and Lindsell but it was not clear how the P, was bound[']. We have now prepared and structurally characterized a nickel(o) complex (2) containing as ligands the tritertiary phosphane tris(2-diphenylphosphinoethyl) amine (np,) and a tetrahedro-tetraphosphorus (P4) molecule. The P, unit is bonded to the metal atom by an apical P atom. The complex [(np,)Ni(P,)] (2) is readily precipitated by reac- tion of the trigonal pyramidal complex of nickel(o)['I (1) with

[*I Prof. Dr. L. Sacconi, Dr. P. Dappono, Dr. S. Midollini Istituto di Chimica Generale e Inorganica dell'Universita. Laboratorio CNR Via J . Nardi, 39. 1-50132 Firenze (Italy)

white phosphorus in tetrahydrofuran (THF). The yellowish brown compound is diamagnetic and only slightly sensitive to air. It is insoluble in all common organic solvents.

has shown that the central nickel atom is bound in a quite regular tetrahedral geometry to the three phosphorus atoms of the np, ligand and to one phosphorus atom of the P, unit (Fig. 1) . The nitrogen atom is not bonded to the metal atom (Ni . . .N=3.09 A). The Ni PI distance, shorter by ca. 0.2 A than the sum of the covalent radii, suggests a d,-d, interaction between nickel and phosphorus. The nickel atom appears to attain the 18 electron configuration.

An X-ray diffraction

Fig. 1. ORTEP plot of [(np,)Ni(P,)j (21. Bond lengths: Ni PI = 1.99(1), Ni P3=2.24(2). PI P2=2.20(3), P2 P2=2.09(3) A. Bond angles: PI Ni P3=109.7(7), P3 Ni P3=109.3(7). P2 P1 P2=56.8(10)"

Experimental

All operations were performed under N, and in oxygen- free THF. A solution of white phosphorus, P, (120 mg, 1 mmol) in T H F (50 ml) was added to a solution of (1) (710 mg, 1 mmol) in T H F (120 ml) at about 0 "C over a period of 15 min. Brown crystals were deposited, filtered off, washed with tetrahydrofuran and dried in a current of N, at room temperature (yield ca. 70%).

Received: February 12. 1979 [Z 231 IE] German version: Angew. Chem. Y I . 510 (1979)

CAS Registry numbers: ( I ) , 52633-73-5: (2). 70355-51-0

[ 1 j A. P. Ginsberg, W. E. Lindsell. J. Am. Chem. SOC. 93, 82 ( I 97 I ) . 121 L. Sacconi, C. A . Ghilardi, C. Mealli, F. Zanobini, Inorg. Chem. 14, 1380

(1975). 131 Rhombohedral, space group R3; a= 10.76 A. a= 108.6"; V = 1061 A': Z = 1:

296 symmetry independent reflections [ Iz2n( l ) j , Philips PW 1100. Mo,,,, graphite monochromator; solution: heavy atom method (programs X-ray 77); refinement: R=0.089.

Stepwise Reaction of Phenylbis(trimethylsi1yl)phos- phane with Phosgene-Isolation of a (Phosphino- methylene)phosphane"l By Rolf Appel and Volker Barthl'l

As a proven chlorinating agent in phosphorus chemistry, phosgene smoothly transforms triorganylphosphanes and triorganylphosphane oxides into the corresponding dichloro- phosphoranes'']. In contrast, its reaction with phenylbis(tri- methylsily1)phosphane (1) leads via elimination of chlorotri- methylsilane to the dichloro(pheny1)phosphane (5), which

['I Prof. Dr. R. Appel, Dipl.-Chem. V. Barth Anorganisch-chemisches Institut der Universitat Gerhard-Domagk-Strasse I. 0-5300 Bonn 1 (Germany)

Aiigew. Chem. Int. Ed. Engl . 18 ( 1 9 7 9 ) No. 6 0 Verlag Chemie, GmbH, 6940 Weinheim, 1979 0570-0X33/79/0606-04~4 $02.50/0 469