EL-GFNF, LEGOFF,STEPHEN E. ULRICHA N D DONALD B. D E ~ E Y
Vol. 80
TABLE I1 POLYMERS OBTAINED FROM BASICBERYLLIVX CARBOXYLATES Dibasic acid chloride
Time, T e m p , hr. OC.
BriO(0COK)ti mmidrs
4
Bt5 16 9Fi 30.5 G5 16 80 19.75 92 17.T, 110
ii.9310 5.4142 -5.7157 f; 0283 ii 0110 C, 1265
Adipic Sebacic 6-Ethyladipic Isophthalic Terephthalic
20. 5, 16 16 19.75 17.5
9.1272 1 8609 7.2021 1.4685 7 31fG 1 4915 7.4809 1 5253 7.309:i 1 4904
65 95 95 95 108
g
Acid chloride, Yield, Carbon, ' '6 mmnles ''L Calcd. Foulid
RCOO = C€f,COO 1.7105 5fi 38.89 1.3323 25 44.26 3.2506 1.4065 49 44.26 3.1317 1.4R74 56 .,. 3.0033 1.4792 83 42.48 1.507(\ 3.0607 1,5075 69 42.48
Adipic Sebacic Sebacic 8-Ethyladipic Isophthalic Terephthalic
10
Acid chloride,
1.7105 1.3323 1.4005 1.4834 1.4792
3.1309 3.0790
RCOO = CH8CHyCOO 3.4062 1 .SO09 25 44.20 3.3939 1.4685 22 48.52 :3 1493 1.4918 30 .,, 3.0967 1.5252 63 47.24 X02GO 1.4904 55 4 7 . 2 4
Hydrogen, '5 Vi.;. Calcd. Ir,nind cosityn
Concn., g./100 ml.
Daysb
9(+)
39.76 4 . 6 7 5.13 0 . 0 4 0.264 44.89 5.79 6 . 3 1 . . Iiisnl. 43 98 5.79 6 . 0 5 . O G 0.179 .. .02 ,256 ... .. 43.T3 3 . 5 6 4 . 2 1 .02 ,309 43.62 3 . 5 6 3.99 .nl ,269
43.91 5.79 5 . 7 2 19.19 6 . 6 8 7 . 0 8
9(+) 5(+) 1
711) 6(-)
..
5(+'1
..
9(+)
Insol. Insol. ., .. . . Insol. 47.40 4.78 4 . 7 7 0.04 0.269 4(i.SO 4.78 4 . 6 2 .04 ,326
I 7(+) 6(-)
RCOO = C&liCOO Sebacic 17.5 93 3.3798 0.434 1.0023 0.434 47 62.36 61.84 4.93 4.72 0 . 0 2 0.280 Isnphthalic 1 7 . 5 100 3 . 3 7 0 2 0 . 3 0 4 0.0168 0 . 3 0 4 59 61.71 61.33 3 . 4 6 3 . 9 5 .02 ,259 Days Iietween prcparatioii and viscosity determination. a Viscosities in toluene. (+) denotes t h a t BerO(RCO?)o could be sublimed o u t ; (i) means that traces could be sublimed o u t ; ( - ) means that none could be sublimed out. So Be40(CsH5C02)scould be sublimed out of the polymers, Imt the sample had a viscosity of zero and was slightly less solublc after the treatment. 'I
transferred t o a melt polymerization apparatus, which is illustrated in Fig. 1. The apparatus was immersed in an oil-bath a t 150-160°, and the system was purged with nitrogen. :\ r x u u m (about 120 mm.) was applied in some cases. T h e mixture snnn bccxne a r e r y viscous fluid, and eventually hardened into a glass. Heating was continued until 110 more bubbles wcrr cibserved corning through the rcnction mixture. Samples of 4 g. oE basic her)-lliurn propionate were heated \Tit11 inolecular cquivnlcnt amounts of adipic acid, sebacic acid and terephthalic acid a t pressures of 120 tnm. and temperatures of 155, 160 anti 200", respectively, for times varying from 3 t o 43 hours. :Ill polrmeric products thus obtained were insoluble and were not further characterized. Free Radical Polymerization of Acrylate-containing Basic Beryllium Carboxylates. Basic Beryllium Acrylate.-Sixtenths of a gram (0.0013 niole) of basic beryllium acrylate \vas dissolved in 73 nil. o f n-heptane and 5 ml. of toluene.
Then 0.0017 g. (0.000007 mole) of benzoyl peroxide (0.5 mole per cent.) was added. a f t e r two hours of heating a t reflux temperature, the mixture was filtered, and the residue washed with low boiling petroleum ether, then drier1 a t reduced pressure. The yield was 0.5 g. or 80%. Anal. Calcd. for ClsHlsOlaBer: C, 45.19; H, 3.80. Found: C, 46.44; H, 4.48. Basic Beryllium Pentapropionate Monoacry1ate.-The procedure was the same as t h a t described in the preceding experiment, using 1.9 g. (0.004 mole) of the basic carboxylate, 0.0126 g. (0.000005 mole) of the initiator (0.13 mole per cent.), and 25 ml. of n-heptane. The yield was 1.4 g. or T4$. Anal. Calcd. for ClsH9sO17Bei: C, 44 26; 13, 3.79. Found: C, 45.12; H, 5.69. VRBAXA, TLimoIs
[C)ONTRIRUTION PROM 'I'fIE S C I I O O L O F CHEMISTRY, R u r G s R s ,
THESTATE ITNIVERSITY
O F S E W JERSEY]
Studies on the Mechanism of the Wurtz Reaction. The Configurations of 2-Bromooc tane, 3 -Me thylnonane and 7 ,%Dimethylte tradecane BY
EUGESE
LEGOFF.'STEPHEN E. ULRICH4ND DOKALD B. DENNEY RECEIVED A U G ~ S 9, T 1957
The absolute configurations of 3-methylnonane and 7,8-dimethyltetradecane have been determined by relating them to 2.bromooctane. From this i t is concluded t h a t the reaction of 2-chlorooctane with sodium ethyl, although heterogeneous definitely proceeds by an S s 2 type of reaction. It also has been shown t h a t the simple Wurtz reaction involving sodium and 2-chlorooctane involves a n inversion of configuration of the carbon atom bearing the chlorine. This furnishes further evidence for the hypothesis that the Wurtz reaction proceeds predominantly through an intermediate sodium alkyl. the aiiion of which then attacks the alkyl halide in a n apparent nucleophilic displacement reaction.
I n the simple Wurtz reaction,2involving metallic sodium and an alkyl halide, presumably a sodium Abstracted from a theyis (1) Henry Rutgers Scholar, 195-1956. submitted b y E . 1,eGoff in partial fulfillment of the R.S. degree. Ju11r.
alkyl is formed first3 and i t subsequently reacts with additional alkyl halide to yield the coupled product 2Sa RNa
+ RX --+ R N a -I- XaX + RX --+ R-R + Sax
(1)
Feb. 5 , 1955
CONFIGURATIONS O F 2-BROMOOCTANE AND 3-LfETHYLNONANE
623
equation 1, is not entirely clear, but there is little doubt that step 2 proceeds predominantly by way of an ionic mechanism. It has been demonstrated4 that in those cases where an optically active hyclxocarbon has resulted from the action of a sodium (f)C6Hi3 alkyl (or alkaryl) on an optically active alkyl CHI CH3 C6Hi3 CH3 CHI halide, the reaction displays characteristics of I ~ a l l I / Cl-C-H + H-C-C-H + H-C-C-H an S1i-2-type reactionj5viz., inversion of configuraI 1 1 I i tion. In all the above cases, the sodium alkyl (or ( - ) CeHu ( - 1 C6H13 CHI meS0 C6Hia alkaryl) was preformed and then was allowed to The projection formulas’ in Charts I and I1 repreact with the alkyl halide. If reaction 2 displays the stereochemical charac- resent absolute configurations if the correct abteristics of an S N reaction, ~ then in those simple solute configuration of D ( +)-glyceraldehyde is acWurtz reactions where the use of an optically ac- cepted.8 Results tive halide, RX,resulted in the production of an From Chart I1 it is seen that (-)-3-methyloptically active product, R-R,‘j the configuration of the product must be inverted relative to the nonane (I) is configurationally the same as ( + ) - 2 starting alkyl halide. In order to confirm this, i t bromooctane when the halogen is replaced by is necessary to relate configurationally the hydro- ethyl, since in the first of the series of reactions an inversion undoubtedly has taken place.g Since carbon product, R-R, to the alkyl halide, RX. I n the present investigation, experimental work (+) -2-bromooctane and (+) -2-chlorooctane are has been performed relating 7,8-dimethyltetradec- configurationally the samesh and (+) -2-chloroane to 2-hromooctane, since previous w 0 r k ~ ~ s ~octane ~ , 6 ~ yielded (+) -3-methylnonane when the forin this Laboratory and elsewhere had been carried mer was treated with sodium ethyl (Chart I), it follows that an inversion of configuration has taken out with 2-bromooctane and 2-chlorooctane. Chart I summarizes the reactions which were place in this last step. This confirms the statecarried out p r e v i o u ~ l y for ~ ~ ,obtaining ~~ optically ment made by Brink, Lane and Wallis4a that ( - ) active 3-methylnonane and 7,s-dimethyltetra- 2-octanol very probably possesses the same configuration as (+)-3-methylnonane. decane from 2-chloro6ctane.
I
I, LiAlH, i 2, PBr3 3, LiAlHdi CH3 H-C--C-H
I
1, LiAIHd 2, PBr3 3. LiAlH4
CeHu
I
I
+
CBHl3 CH,
(-1
I1
Chart I1 summarizes the reactions which were carried out in this investigation to relate 3-methylnonane (I) and ’7,s-dimethyltetradecane (11) configurationally to 2-bromooctane. (4) (a) N. Brink, J . Lane and E. Wallis, THISJOCRXAL, 66, 943 (1943); (b) R. L. Letsinger, i b i d . , 70, 406 (1948); (c) R. L. Letsinger and J . G. Traynham, ibid., 72, 849 (1950); (d) S. E. Ulrich, F. H. Gentes, J. F . Lane and E. S. Wallis, ibid., 72, 5127 (1950); (e) R. L. Letsinger, L. G. Maury and R. L. Burwell, Jr., ibid., 73, 2373 (1951). ( 5 ) C. K . Ingold, “Structure and Mechanism in Organic Chemis1953, p. 380 and p. 386. try,” Cornell University Press, Ithaca, N. Y., (6) (a) E. O t t , A. Behr and R. Schroter, Be?., 61, 2124 (1928); (h) J. F. Lane and S. E. Ulrich, THIS J O U R N A L , 72, 5132 (1950).
(7) The usual convention is used, uiz., heavy lines represent bonds projecting out of the plane of t h e paper toward the observer. (8) (a) J. M. Bijvoet, A. F. Peerdeman and A. J. van Bommel, X a t w e , 168, 271 (1951); (b) J. F. Lane, S c i e n c e , 113, 577 (1951); (c) J. M. Bijvoet, E n d e a v o i w , 14, 71 (1955); (d) K. Freudenherg, Bcr., 47, 2027 (1914); M. L. Wolfrom, R. U. Lemieux, S. M. Olin and D. I. Weisblat, THIS J O U R N A L , 71, 4057 (1949); (e) P. A. Levene and A. Rothen, J . Org. Chem., 1, 76 (1936); K . B. Wiberg, THIS JOURNAL, 74, 3891 (1952); (f) W. von E. Doering and R. W. Young, ibid., 74, 2997 (1952): ( g ) A. J. H Houssa, J. Kenyon and H. Phillips, J . Chem. SOL.,1700 (1929). (9) J. A. Mills and W. Klyne in “Progress in Stereochemistry,” edited by W. Klyne, Butterworths Scientific Publications, London, 1954, p. 197.
621
EUGENE LEGOFF,STEPHEN E. ULRICHAND DONALD B. DENNEY
Vol. 80
was dried with sodium sulfate and then the ether w a s flash Also, from Chart 11, it is seen that ( - ) - 7 , S Vacuum distillation of the residual oil yielded 116 dimethyltetradecanelO (11) is configurationally the distilled. g. (80%) of (-)-diethyl sec-octglmalonate, b.p. 124-133" same as (+)-2-bromooctane when the halogeii is (2.3 mm.), T Z ~ ~1.4316, D nzO~1.4338, dZ04 O.g4S, [ a l 2 0 ~ replaced by sec-octyl. Therefore, since (+)-a- -0.25" (homogeneous). (-)-3-Methylnonoic Acid (IV).-To a hot solution of 35 bromooctane is configurationally the same as (+)-2-~hlorooctane,~~ an inversion of configuration g. of potassium hydroxide in 80 ml. of water, there was added in portions 60 g. (0.22 mole) of (-)-diethyl sec-octylof the carbon atom bearing the chlorine must have malonate. When the reaction mixture had cleared (ca. 30 taken place in the Wurtz reaction when (-)-2minutes), it was cooled and poured carefully into 200 ml. of chlorooctane was allowed to react with sodium to 12 N hydrochloric acid. T h e resultirig organic material yield ( -)-7,s-dimethyltetradecane (Chart I). was extracted with four 100-ml. portions of ether. The combined ether washings were dried with sodium sulfate Thus, further credence is given to the hypothesis3~.'" atid the ether was removed by distillation. The residual that the Wurtz reaction procecds by way of an oil was heated on a steam-bath overnight and then heated intermediate sodium alkyl, the anion of which then for 2 hours at 125-140°, one hour a t 140-155°, and 15 attacks the alkyl halide in a typical nucleophilic iniiiutes at 185-195". Vacuum distillation of the remaiiiing liquid gave 32.7 g. (86%) of product, b.p. 115-123' ( 2 . t substitution process. l t l l l l . ) , '?Lz'D 1.1321, 1EZ0D 1.4340, dZo4 0.893, [a]"D -4.20 Whether the sodium alkyl reacts wit11 the alkyl (homogeneous), Previously reported constants13 for 3halide to give inverted or extensively racemized rnethylnonoic acid are b.p. 133" (8 mni.), azo40.809, n Z 5 D product depends both on the nature of the sodium 1.433'1, [ a ] " D +O.i&". amide was prepared in the usual manner, 1n.p. 93.8alkyl and of the alkyl halide. For example, so- 9 4 .The 8O. dium ethyl reacts with optically active 2-chloroocAnal. Calcd. for C~OHZIOX: C, 70.12; 13, 12.36; N, tane to yield optically active 3-methylnonane 8.18. Found: C, 70.34; H, 12.08; N, 8.08. (20% racemization)*d while the same sodium alkyl (-)-3-Methyl-l-nonanol.--Under nitrogen atmosphere, reacts with optically active 2-bromooctane to 10.0 g. (0.26 mole) of lithium aluminum hydride was added yield essentially inactive hydrocarbon (97% race- to 150 ml. of sodium-dried ether. T o this was added with 29.6 g. (0.17 mole) of (-)-3-niethylnonoic acid m i ~ a t i o n ) . ~ On " the other hand, sodium allyl re- stirring dissolved in 100 ml. of sodium-dried ether over a period of acts with optically active 2-bromooctane to yield 90 minutes a t room temperature. After i t had been allowed optically active 4-methyl-1-decene (13 to 21% to stand for 1'7 hours a t room temperature, the reaction mi was carefully poured into an ice and sulfuric acid nii racemization) .& A plausible explanation for this ture ture. The mixture TWS washed with two 100-nil. portions behavior is given by Lane and Ulrich.'jb arid one 50-1111. portion of ether and the combined ether The percentage of racernization i n the reaction of washings were dried with sodium sulfate and the ether flash sodium with (-)-2-chloruiictane is unknown since distil!ed. The residual liquid was t!ieri vacuum distilled. resulted 22 g. ( 8 2 % ) of product, 13.p. R8-8!1" (2.5the maximal rotation of opticdly active 7,s-di- There 3.0 mm.),n2% 1.4377, d20r 0.879, [ a j Z n-3.47' ~ (lioruomethyltetradecane is unknown. Work is now geneous). Previously reported constants13 for ( f 1-3being carried out in this Laboratory to prepare the methyl-1-nonanol are h . p . 1 2 ' (24 m i i i . ) , d 2 j 4 !!.837, 1 ~ ~ ~ 1 1 pure meso and optically acti1Y-e forms of this hydro- 1.4318, [a]"D +0.4:3". The naplithylurethan was obtained as white nectlles from carbon to determine the extent of this racemization. alcohol-water in the usual manner, m . p . 63.1-fi6.1°. A Acknowledgment.-The generous help afforded previously reported value" for the naplithylurctliaii of racemic 3-methyl-1-nonanol is m.p. 49". by grants of the Research Council of Rutgers, The AmZ. Calcd. for C21H2902rUI: S,4.28. Found: S , 4.35. State University of New Jersey, is gratefully :IC(+)-l-Bromo-3-metbylnonane.-To 10.2 g. (0.12 mole) knowledged. of ( - )-3-methyl-l-nonanol, cooled in a Dry Ice-ethanolbath, x a s added 5 . 7 ml. (0.06 mole) of phosphorus tribroExperimental mide in several small portions. The reaction mixture was ( - )-2-Bromooctane .-( - )-2-Bromoiictane ( [ q I z o ~allowed to warm to room temperature, stand overnight, and -31.8' (homogeneous), b.p. 80" (19 nim.), n z o 1.4uO6) ~ was prepared from (+)-2-octanol12 ( [ a ] % +8.13" (holnogeneous), n z o1.423
