492 COMMUNICATIONS TO THE EDITOR Vol. 53

The present a reement factor is R = 2 1 1 FO I - 1 Foll/Z: I Fof = 0.14 for the 889 observed re- flections.

Acknowledgments.-We wish to thank Dr. 51. F. Hawthorne for supplying us with several B9H15R derivatives until this favorable X-ray problem was chosen. We also thank the Office of Naval Research and the Office of Ordnance Re- search for support. DEPARTMENT OF CHEMISTRY FREDERICK E. WAX HARVARD UNIVERSITY PACL G. SIMPSON CAMBRIDGE 38, MASSACHUSETTS WILLIAM N. LIPSCOMB

RECEIVED NOVEMBER 18, 1960

A NEW SYNTHESIS OF CYCLIC DIACYL PEROXIDES. DIPHENOYL PEROXIDE FROM PHENANTHRENE-

QUINONE oia A PHOSPHORANE DERIVATIVE' S i r :

We have developed a convenient method for the preparation of certain cyclic diacyl peroxides,2 for instance diphenoyl peroxide (11), a substance in which the peroxidic linkage is part of an eight- membered ring.

I

The results of a typical experiment are: a mix- ture of phenanthrenequinone (I, 4.16 g.), trimethyl phosphite (2.48 g., one mole equivalent; an excess should be avoided) and methylene chloride (100 1111.) was kept 0.5 hr. a t room temperature, under nitrogen. The pale yellow solution was cooled to -70" and treated with ozone from a Welsbach T-23 ozonator. The reddish-brown color of the solution was discharged sharply as the ozone consumption reached the value of one mole equivalent. The reaction mixture was flushed with nitrogen and filtered to remove some phenanthrenequinone (0.4 1 8.). The methylene chloride was removed in ziacuo at teiiiperatures not exceeding 20". The residue was extracted with cold methanol, which left 3.8 g. of crude peroxide, contaminated with some phenanthrenequinone. From this material, 2.4 g. (Z070 over-all yield) of crystalline diphenoyl per- oxide (11) of over 9G% purity (iodimetric assay) was obtained after one recrystallization from methylene chloride-methanol (a solution containing 10 ml. of methylene chloride and 10 ml. of methanol per gram of crude peroxide was concentrated in zxzci~o, below 20").

Diphenoyl peroxide (11) is a colorless substance which can be preserved a t low temperature but which explodes violently when heated to ca. 70" or under impact. Calcd. for C14H804: C, 70.0; H,

(1) Acknowledgment is made t o the Donors of the Petloleuin Research Fund administered by the American Chemical Society for partial support of this Research (Grant 2813-A) and t o the National Cancer Insti tute of the Xational Institutes of Health (Grant CY-47C9).

(2) For a discussion of cyclic diacyl peroxides, see F D. Greene and W W. Rees, J. Am. Chem. Soc., 82, 893 (1960) aud references therein.

3.3; 0, 26.7; mol. wt., 240; found C, 70.0; H, 3.2. 0,26.5; mol. wt., 219 (cryoscopic in benzene); a single, sharp and strong band a t 5.68 p. 2,2'- Diphenic anhydride was produced in over SOTo yield from the reaction of the peroxide I1 with tri- phenylph~sphine~ (or trimethyl phosphite). 2,2'- Diphenic acid was obtained in the iodimetric assay of the peroxide 11.

.A crystalline 1: 1 adduct IV can be isolateda from the reaction of phenanthrenequinone I with trimethyl phosphite. Ozonolysis of the adduct IY in methylene chloride as described above gave a mixture shown to contain diphenoyl peroxide (11, ca. 77% yield), phenanthrenequinone (I, ca. 205& yield) and trimethyl phosphate (111, ca. 95Yo yield), by a combination of infrared spectrometric and iodimetric assays. (Pure peroxide, 11, was again isolated in 46-50y0 yields after one recrystalliza- tion.) The product of a comparable ozonolys~s~ of the crystalline 1 : 1 adduct derived from benzil and trimethyl phosphite consists of benzoyl per- oxide (ca. 3iVc) benzil (ca. 52Cj,) and trimethyl phosphate. -4 possible mechanism for this new reaction has bee11 a d ~ a n c e d . ~

* '\, \ ,,' CI O( tl

I' y- or I f ' U(?H

(3) M. A. Greenbaum, D. B. Denney and A. K. Hoffinann, i b i d . ,

(4) F. Ramirez and N. B. Desai, i b i d . , 82, 2A,52 (1900). ( 5 ) F. Ramirez, R . B. Mitra and N. B. Desai, i b i d . , 82, 57133 (1900).

78, 2563 (1956).

DEPARTMENT OF CHEMISTRS FAL~STO RAMIREZ STATE UNIVERSITY OF XEW YORK iY. B. DESAI LOSC ISLAXD CENTER R. B. MITRA OYSTER BAY, S. Y .

IZECEIVE~ SOT.~EXBER 29, l O G O

DEHYDROHALOGENATION OF SIMPLE ALKYL

CARBENE INTERMEDIATES. EXTENT OF HALIDES BY STRONG BASE ; EVIDENCE OF

e-ELIMINATION' S i r :

I t was shown tliat iieoalkyl halides react wit11 strong base via n-eliininntion and subsequent inscr- tiou to give cyclopropanes. S i n ~ e ~ ~ , ~ isobutyl chlo- ride and soc1iu:ii or propyl sodimi yields rnctliyl- cyclopropaue ant1 isobutyleiie as major products it was of interest to determine the niechanisiii b;: which they are for-iiied. ~\lethylcyclopropane caii arise via a-elimination, whereas isobut)-lene ma!- result by either E2 (,8) elimination andl'or a-elini- ination, followed by hydride transfer.

(1) (a) Presented in part a t the Mfeting-in-Miniatilre. New York (b) J. G. Berger, hf S.

(2) L. Friedman and J . 0. Berger, J . A i n . Chein. Soc.. 83, 500 (1961).

(3) (a) F. E. Condon and D. E. Smith, ibid., 69, 965 (1947). (b) Recently, W. Kirmse, German Chemical Society Local Section Meeting, Mainz-Weisbaden, July 21, 1960; abstracted in Angcza. Chrm., 72, 716 (1900). reported tha t a,a-dideuteroisobutyl chloride re- acts with sodium or potassium but not with lithium t o give methyl- cyclopropane B Z U u-elimination and isobutylene by concurrent (II and P elimination. These results complement those of t h e present investi- gation. (c) X O ~ E ADDED I N PROOP.-For a complete account see W. Kirmse and W. van E. Doering, Tetrahedron, 11, 266 (1960).

Section, 4.C S . , March 11. 1900, paper H-9. Thesis, New York University, June 19GO.

Jan. 20, 1901 COMMUNICATIONS TO THE EDITOR 493

TABLE I

KEACTION OF BUTYL HALIDES WITH STRONG BASES

Halide

n-BuC1-1-d, n-BuC1 n-BuBr n-BuI i.BuC1-l-dp i-BuC1 i-BuBr i-BuI s-BuC1 n-BuC1 n-BuBr i-BuC1 i-BuBr n-BuCI i-BuC1

Base

PhNad Phh'a PhNa PhNa PhNa PhKa PhNa PhEa PhNa NaNHP KaXH.1 NaiYHp NaNH2 NaOMe NaOMe

c Dehydrohalogenation Products" - trans- Metbyl- c is -2-

CI Alkane 1-Butene Isobutene 2-Butene cyclopropane Butene

7 .7 4 . 5 7

12 9 . 7 5 . 0 3 . 2 7 . 5 t 0.5 4 . 5

89 91

71

c- 10

47 98 95

99

t' t 7 5 . 5

57 t 63 t 73 t 86 0.7

30 t t

96 0 . 7 99 0 . 3

0 . 4 98 1 . 6

3 .6 t 3 .7 t 4 7 2 . 6 10

33 t 32 t 24 t

5 .1 1.1 23

1 .2 t 0 . 6 t 2 . 5 0 . 7 0 .4 t 0 .4 t

0 4

Tield,b Yc a-Elim- "ib inationc

30 94f 40 94 2 5 0 94 20 65 59 89' 59 89 31 62 29 13 Mh -J

27 30 45* 15 50 7 50k 1 8 10 Oh 0

of halides -100%. Estimated (see text)

a yo composition. Products analyzed, separated and identified by V.P.C. Conversion Average of two or more runs unless noted. S N ~ products account for balance i .e . , 100% - 70 yield.

except where noted. Difference from 100 is extent of E2 Exclusive of s N 2 process. Reaction conditions: 10% excess base: PhNa suspension in decane (loo'), NaSH2 in diethyl Carbitol (reflux, ca. 18O0), KaOMe in diethyl Carbitol (reflux). e Trace < O . l % . f Mass spectrographic analysis. 0 Total yield of products reproducible, but '% composition variable as a result of presently unknown factors. Yield of S N 2 product is in good agreement with that obtained by Wurtz-Fittig reaction, using PhBr, n-BuBr and Na. See R. R. Read, L. S. Foster, A. Russell and V. L. Simril, "Organic Syntheses," Coll. Vol. 111, John Wiley and Sons, Inc., New York, N. Y., 1955, p. 157. h Single experiment.

ri

It is now reported that n-butyl chloride and iso- butyl chloride3b are dehydrohalogenated by phenyl sodium or sodium predominantly through a-elimina- tion. Thus, 1,1-dideuterobutyl chloride and phenyl sodium give monodeuterornethylcyclopropane (4Y0) and a mixture of mono-(-9070) and di-(-G%) deutero-1-butenes4 in 30y0 overall yield. 1,l-DI- deuteroisobutyl chloride and phenyl sodium give rnonodeuteroinethylcyclopropane (3770) and a mix- ture of mono- ( -5270) and di- (-11%) deuteroiso- butylenes4 in GOYo overall yield. Therefore, exclusive of S N ~ reaction, a-elimination occurs in the former case to the extent of 94700, while in the latter to 89%. Using the yield of methylcyclo- propane in each series as the criterion, the extent of a-elimination occurring with undeuterated butyl halides can be estimated (Table I).5

Thus, it may be inferred from the experimental data that n-butyl halides (X = C1, Br, I) undergo a-elimination with phenyl sodium to the extent of 94, 94 and 6l%, respectively, whereas with the corresponding isobutyl halides a-elimination occurs to the extent of 89, 62 and 137,. Similar data are

(4) By mass spectrographic analysis. (5) For yield of methylcyclopropane f rom correspovding tosyl-

hydrazones see: L. Friedmdn and H. Shechter, J, A m . Chcm. Sac., 81, 5512 (1959).

obtained when sodium [Wurtz reaction] is used. These results indicate how steric more than induc- tive factors affect the course of dehydrohalogena- tiom6 With weaker bases such as sodamide the extent of a-elimination is markedly reduced. However, n-butyl chloride undergoes a-elimination (-1 0%) with sodium inethoxide while isobutyl chloride does not. Hence, in addition to steric factors, the extent of a-elimination appears to be proportional to the strength of the base employed.

%-Propyl halides (X = I, Br, C1) react with phenyl sodium to give dehydrohalogenation prod- ucts (20-50% yield) of which 2-4% is cyclopro- pane. Similarly, ethylcyclopropane (4.5%) is obtained from n-amyl chloride.' It is of interest to note that n-propyl benzenesulfonate reacts with phenyl sodium to give elimination products in only 1% yield of which 4% is cyclopropane. sec-Butyl halides do not yield inethylcyclopropane. The degree of a-elimination with secondary halides is presently under investigation.

It is therefore apparent that dehydrohalogena- tion of primary halides with strong base in suitable media occurs predominantly via a-elimination.8

(6) These factors are amply discussed arid documented with respect t o E2 3s. 5N2 reactions. C. I(. Ingold, "Structure and hlechanisrn in Organic Chemistry," Cornell University Press, I thaca, N. Y., 1'333, chap. VII I .

(7) Cf. G. L. Closs, Abstracts of Papers, 138th Meeting of the American Chemical Society. h-ew York, h'. Y., Sept., 1960, p. 9 - 0 .

(8) For earlier work in this area see: D. G. Hill, W. A. Judge, P S. Skell, S. W. Kantor and C. R. Hauser, J. A m . Chem. Sac., 74, 5599 (1952); S. 11. Luck, D. G. Hill, A. T. Stewart, Jr. and C. R. Hauser, ibid., 81, 2784 (1959).

DEPARTMENT OF CHEMISTRY XEW YORK UNIVERSITY L. FRIEDMAN UNIVERSITY HEIGHTS JOEL G. BERGER XEW YORK 53, KEW YORK

RECEIVED OCTOBER 25. 1060