970
K. L. RIKEHART, J R . , D. E. BUBLITZ AKD D. H. GUSTAFSON
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Experimental
Materials.lZ-( )-trans-a,r-Dimethylallyl-P-nitrobenzoate carbonyl-180, 3.707, m.p. 46.2-47.4', [ a ]% 41.6' (CHCl3) (lit.3 m . p 45.7-46.7 , [CY]% 42.5') was prepared as described earlier3 from ( )-trans-a,?-dimethylallyl acid phthalate, m.p. 80.5-82.8", [ a ] " D 38.0" (14, C 1.25, CHCl3). ( )-trans-or,?-Dimethylallyl p-nitrobenzoate-ether-l80, 2.51 %c l80, m.p. 45.0-46.0", [ a ]* 5 41.9' ~ (CHC13) was prepared as follows. Crotona1dehyde-carbonyl-l8O,2.907, l80,b.p. 98-102", n Z 51.4337, ~ was obtained by equilibration of freshly distilled crotonaldehyde with 180-water, ca. 5% l80, according to a general procedure.20 This was converted' t o trans-or,y-dimethylallyl alcohol-180 which in turn was converted to the acid phthalate derivative, 2 . 8 9 7 ~ l80, m.p. 88.0-89.5". Resolution4 gave opticalfy pure trans-a,?-dimethylallyl acid phthalate-ether-180. 2.82Tc lSO, m . p . 76.6-78.1", [aIz6D38.0". This was converted to '80-labeled ( )-trans-o,-pdimethylallyl alcohol by reduction with lithium aluminum h ~ d r i d e . ~ Reaction of the alcohol with p-nitrobenzoyl chloride gave ether-I80-( )-I. T h a t this material was discretely labeled in the ether oxygen position was shown as follows. A small portion of the labeled ester, 2.51% l80,was reduced3 t o trans-a,r-dimethylallyl alcohol which was reconverted to the p-nitrobenzoate I and acid phthalate derivatives. The p-nitrobenzoate derivative I contained 2.527' l80; the acid phthalate contained 2.49% l80. These experiments prove t h a t the p-nitrobenzoate derivative is labeled exclusively in the ether position and t h a t the transformations used to determine the lSO-distribution in the unsolvolyzed p-nitrobenzoate do not lead t o loss or scrambling of the lSO-label. The aqueous acetonelo was prepared from purifiedzl acetone and conductivity water.
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(20) H.L. Goeringand R. E. Dilgren, J . A m . C h e m . Soc., 82, 5744 (1960) (21) J. K . Kochi and G . S. H a m m o n d , i b i d . , 'IS, 3443 (1953).
[COSTRIBUTIOS F R O M
THE XOYES
Vol. 83
Kinetic Experiments.-All concentration are given for 25" . The polarimetric and titrimetric rates were determined b y methods described earlier.3 I n the polarimetric experiments the total change in rotation was over 2' and individual measurements were reproducible to within 0.01". For the titrimetric experiments reactions were followed by titrating 5-ml. aliquots with 0.0485 LV aqueous sodium hydroxide to the brom thymol blue end-point. The change in titer for a typical experiment was about 5 ml. and titrations were reproducible to within 0.005 ml. Determination of 180-Equilibration and Scrambling.-A11 l S 0 contents were determined3 in triplicate and the average deviation from the mean was less than 1%;. Samples used for 180-determinations were shown to be pure by their physical properties including infrared spectra. The rate of '80-equilibration (eq. 2 ) was determined by the method described earlier.6 T h e data are summarized in Table 11.
Rates of 180-scrambling in the enantiomers (eq. 3) were also determined by a method described earlier.3 Pertinent data are given in Tables 111and IT. Determination of Optical Purity of ( +)-trans-a,r-Dimethylallyl Acid Phthalate.-The optical purity was established by a modification of a n isotope dilution method described earlier . 6 z 2 Equal weights of ( +)-trans-a,y-dimethylallyl acid phthalate, [ u ] ? ~ D38.0" ( I 4, c 1.25, CHCl?), and dl-trans-a,y-dimethylallyl acid phthalate, 5.90 f O.Olyc 180, were mixed and the resulting mixture resolved? to a constant rotation of [a]"D 38.0" ( I 4, c 1.25, CHC1)3. The latter had an 180-content of 1.98 =t0.0270. From these data it can be shown6 t h a t acid phthalate, [ a I z 5 D 38.0", is 100 57' optically pure.
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(22) J S Berson and D A Ben-Efraim, d i d , 81, 4083 (1959)
CHEMICAL LABORATORY, UNIVERSITY O F
ILLINOIS,
URBANA,
ILL.]
Organic Chemistry of Ferrocene. V1.l Acetylation of Mono-, Di- and Tri-bridged Ferrocenes2 BY
KENNETH L. RINEHART, J R . , 3 DONALD E. BUBLITZA N D DAVIDH. GUSTAFSON RECEIVEDAUGUST29, 1962
Synthesis of the isomeric bis- and tris-( trimethylene)-ferrocenes has been achieved. These compounds and the mono-bridged analog have been acetylated and the ratios of the isomeric acetyl products have been determined Cyclization of certain bridged ferrocene-propionic acids has been shown to give homoannular ketonic products, as well as the expected heteroannular compounds Nuclear magnetic resonance spectra of the compounds prepared are discussed.
Since the original reports4m5of the preparation of a bridged ferrocene, 1,l'-( a-ketotrimethylene) -ferrocene (Ia), considerable interest has been displayed in compounds of this type and a number of other monobridged compounds have been prepared, as Ib,l I C , ~ . ~I d- j*6 Iej9 If,1oIg,' Ih,lo Ii.11.12 Recently, too, the di-bridged ferrocene X I and its a-keto derivative X have been reported by Schlogl and Seiler.I3 The ketone X was prepared by them by cyclization of 1,l'trimethyleneferrocene-3-propionic acid ( IX),I4 which (1) Paper V,K. I-. Rinehart, J r . , R . J. C u r b y , Jr., D . H. Gustafson, K. G. Harbison. R . E . Rozak and D . E . Bublitz. J . A m . Chem Soc., 84, 3263 (1962) ( 2 ) Presented in part a t the l 4 l s t S a t i o n a l A.C.S. hfeeting, Washington, L). C , M a r c h 20-29, 19632; cf. Abstracts, p , 1 9 - 0 . (3) Alfred P . Sloan Foundation Fellow. f-1) K. I,. Rinehart, J r . , a n d R. J . Curby, J r , J . A m . Chem. S o c . , 1 9 , :4290 (1957) ( 5 ) I n the P h I). 'Thesis of hf. Rosenblum ( H a r v a r d University, August, 193.3) i t is noted t h a t R B. Woodward a n d E . Csendes obtained compound l a , a m p . is given, and a tentative structiire is assigned, ( 6 ) A . I,~ittringhausand IV. Kullick. A x g e w , C h e n . , I O , 4:38 (19:8), (7) K Schlogl a n d H. Seiler, A f o n i l f s h . ,91, 79 (1960). (8) E . A Hill and J H Richards, J . A m Chem S o c . , 83, 4216 (19f:I). f 9 ) R I. Schaaf, P. T Kan and C .T. l.enk, J . O r g . C h e m . , 26, 1790 (1961). 110) K 1. Kinehart, J r . , A K . Frerichs, P. A K i t t l e , I,. F. Westman, I) €3. G u s t a f s o n . R. 1,. P r u e t t a n d J E . IrfcMahon, J . A m . C h e m . Soc., 82, 1111 !1400) ( 1 1 ) 'I' 4 hlashhurn, J r , and C R . Hauser, J . O r # . C h e m . , 2 6 , 1671 f I(if;I ). (12) I
