234
Organometallics 1986, 5, 234-237
analogues. Acknowledgment. This research has been supported by the National &%nce F'Oundation Grants CHE-8119060 and CHE-8421282 at Washington State University and by the New Mexico Research Bond Fund a t Eastern New
Mexico University. Registry No. [Ir(CO)Cl(dppm)lz, 99511-21-4;[Ir(COD)Cl],, 12112-67-3; [ Ir (CO)Cl(dam)] *, 99511-22-5; [Ir (CO)Cl(cot),] 51812-37-4; [Ph(CO)Cl(dam)lz, 99511-23-6;[Ph(CO)Cl(dppm)lz, 99511-24-7.
,,
Palladium-Catalyzed Additions of Amines to Conjugated Dienes: Alteration of Behavior of (Tripheny1phosphine)palladium Catalysts with Amine Hydroiodide Salts Robert W. Armbruster, Michael M. Morgan, James L. Schmidt, Chun Man Lau, Rose M. Riley, Daniel L. Zabrowski, and Harold A. Dieck" Department of Chemistty, Saint Louis University, Saint Louis, Missouri 63 103 Received June 24, 1985
When amine hydroiodide salts are present, (tripheny1phosphine)paliadiumcatalyst systems are capable of effecting the addition of primary and secondary amines to certain conjugated dienes. The generality and mechanistic aspects of these reactions were investigated.
Introduction We have found that amine hydroiodide salts are capable of altering the behavior of (tripheny1phosphine)palladium catalyst systems in reactions of amines with conjugated dienes. Such reactions produce 1:l adducts which, in the case of 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene, consist primarily of products resulting from a 1,4-addition of the N-H moiety across the diene system. These addition products are obtained in fair to good yields with only traces of 1,2-addition products and octadienyl amines (1:2 adducts) being formed. Literature reports of similar systems using (tripheny1phosphine)palladium catalysts without the amine hydroiodide salt indicate that octadienylamines are the major products.lI2 Octadienylamines are also the major products in reactions employing phosphonite3v4and l,&cyclooctadienyl ligand^.^ Other reports indicate that when a diphosphine ligand, e.g., 1,2-bis(diphenylphosphino)ethane,is substituted for triphenylphosphine (no amine hydroiodide salt), 1:l adducts are obtained:,' but in some cases the products (1)(a) Takahashi, S.; Shibano, T.; Hagihara, N. Bull. Chem. SOC.Jpn. 1968,41,454.(b) Shryne, T. M. US.Patent 3530187,1970;Chem. Abstr. 1970, 73, 930615. (c) Walker, W. E.; Manyik, R. M.; Adkins, K. E.; Farmer, M. L. Tetrahedron Lett. 1970,43,3817.(d) Hata, T.; Takahashi, K.; Miyaki, A. Japan 72 25045,1972;Chem. Abstr. 1972,77,101117. (e) Watanabe, H.; Nagai, A.; Saito, M.; Tanaka, H.; Nagai, Y. Asaki Garasu Kogyo Gijutsu Shoreikai 1981,38,111;Chem. Abstr. 1982,97,181653. (0 Keim, W.; Roeper, M.; Schieren, M. J. Mol. Catal. 1983,20, 139. (2)(a) Mitsuyasu, T.; Hara, M.; Tsuji, J. J.Chem. SOC. D 1971,1345. (b) Tsuji, J. Japan 7522014, 1975;Chem. Abstr. 1975,84,16736. (3)(a) Hobbs, C.F.; McMackins, D. E. U.S. Patent 4 100 194, 1978; Chem. Abstr. 1979,90,22297.(b) Hobbs, C.F.; McMackins, D. E. U.S. Patent 4130590,1978;Chem. Abstr. 1979,90,137247. (4)(a) Hobbs, C. F.; McMackins, D. E. US.Patent 4 100 196, 1978; Chem. Abstr. 1979,90,5894. (b) Keim, W.;Kurtz, K. R.; Roeper, M. J . Mol. Catal. 1983,20, 129. (5)Stone, F.G. A.; Green, M.; Scholes, G.; Spencer, J. L. U.S. Patent 4104471, 1978; Chem. Abstr. 1979,90,87479. (6)(a) Takahashi, K.; Miyake, A.; Hata, G. Bull. Chem. SOC.J p n . 1972, 45, 1183. (b) Takahashi, K.; Hata, T. and Miyake, A. Japan 7025321,1972; Chem. Abstr. 1972, 77, 101114.
0276-7333/86/2305-0234$01.50/0
consist of considerable quantities of l12-additionproducts. Another group has had some success in obtaining 1:l adducts using a palladium acetoacetate-tributylphosphinetriethyl aluminum catalyst system, but reports that octadienylamines are the major products in reactions using 1,3-butadiene or isoprene.8 In this paper we report the results of our studies concerned with the generality and mechanistic aspects of these reactions incorporating the amine hydroiodide salts and offer an explanation for the poor or nonexistent yields of 1,2-addition products.
Results and Discussion The results of some of our experiments involving reactions of equimolar amounts of amines and dienes using a catalyst precursor system of palladium acetate, triphenylphosphine, and triethylammonium iodide in quantities of 1,2, and 10 mol ?'& ,respectively, are listed in Table I. No 1:l adducts were obtained if any one of these substances were excluded. The minimum quantity of amine salt needed for optimum conditions (rate and yield) seems to differ for each reaction although we found no noticeable improvement when more than 10 mol % was used. The reaction of diethylamine with isoprene seems to proceed as well with 3 mol % amine salt as with 10 mol % salt, but the rates are slower when quantities less than 3 mol % are used. Similar results were obtained by using other amine hydroiodide salts. Successful results are also possible using reduced catalyst quantities as evidenced by the reaction of isoprene with diethylamine using 0.2 mol % palladium acetate, 0.4 mol % triphenylphosphine, and 1.0 mol % triethylammonium iodide which resulted in 52% isolated yield of a mixture of N-(2-methyl-2-buten(7)Hobbs, C.F.; McMackins, D. E. US. Patent 4129901,1978;Chem. Abstr. 1979,90,54459.U S . Patent 4204997,1980;Chem. Abstr. 1980, 93, 185742. (8)Dzhemilev, U.M.; Yakupova, A. 2.; Minsker, S. K.; Tolstikov, G. A. J . Org. Chem. USSR, Engl. Transl. 1979,15, 104.
0 1986 American Chemical Society
Pd-Catalyzed Additions of Amines to Conjugated Dienes
Organometallics, Vol. 5, No. 2, 1986 235
Table I. Addition Reactions of Amines to Conjugated Dienesa reaction reaction time, h amine temp, “C products
diene isoprene
diethylamine
100-105
12
1,3-butadiene 1,3-butadiene
diethylamine p-toluidine
100-105 100-105
52
2,3-dimethyl-1,3-butadiene diethylamine n-butylamine 2,3-dimethyl-1,3-butadiene 2,3-dimethyl-1,3-butadiene piperidine diethylamine 1,3-cyclohexadiene aniline l,3-hexadienec
100-105 100-105 100-105 115-120 100-105
43 170 48 25
125-130
18
aniline
2,4-hexadienec
12
18
% yieldb
N-(2-methyl-2-buten-l-yl)-N,N-diethylamine, I N-(3-methyl-2-buten-l-yl)-N.N-diethvlamine~ I1 N-(2-buten-l-yl)-NJV-ðylamineN-(l-buten-3-yl)-p-toluidine, I11 N-(2-buten-l-yl)-p-toluidine, IV N-( 2,3-dimethyl-2-buten-l-yl)-N,N-diethylamine, V N-(2,3-dimethyl-2-buten-l-yl)-N-butylamine N-(2,3-dimethyl-P-buten-l-yl)piperidine N-(2-cyclohexenyl)-N,N-diethylamine N-(3-hexen-2-yl)aniline, VI N-(2-hexen-4-yl)aniline,VI1 VI VI1
(25) (51) 45 0 (8)
40 (66) 61 2 1 (32) 61
31 (45) (4.5) (30) (2.5)
aUnless otherwise noted, reactions used 1:l molar ratios of dienes and amines with 1 mol % P ~ ( O A C 2) ~mol , % Ph3P and 10 mol 70 Et3NH+I-. bIsolated yields. Yields in parentheses were determined by GLC. c 5 mol % P ~ ( O A C 10 ) ~ mol , % Ph3P, 10 mol % Et3NH+I-.
1-y1)-N,N-diethylamine (I) and N-(3-methyl-2-buten-ly1)-N,N-diethylamine (11) in an approximate ratio of 1:2 (115 “C, 24 h).
I
Scheme I R3NH+I-
“Pd(0)”
I I
H-Pd-I
-*
= J.-
I
-
H-Pd-I
I
I1
Poorer yields and slower reaction rates resulted when amine hydrobromide salts were used. The reaction between diethylamine and isoprene in the presence of triethylammonium iodide yielded 25% I and 51% 11. However, in the presence of triethylammonium bromide only 14% I and 30% I1 were formed (12 h). No change in yield occurred upon extending the reaction time. Only traces of the 1:l products were observed in reactions using amine hydrochloride salts. Parallel results were obtained by using 1,2-bis(dipheny1phosphino)ethane as the activating ligand, e.g., substituting 1mol % of this ligand for triphenylphosphine gave 9% I and 50% I1 in the reaction of diethylamine and isoprene (100 “C, 54 h) and 81% N-(2,3-dimethyl-2-buten-1-y1)-N,N-diethylamine (V) in the reaction of diethylamine with 2,3-dimethyl-l,3-butadiene (100 “C, 43 h). However, poor yields (less than 5%) were obtained when either tri-o-tolylphosphine or triphenylarsine was used. The reaction of p-toluidine and 1,3-butadiene resulted in predominately 1P-addition product, 66% N-(2-buten1-y1)-p-toluidine(IV) and 8% N-(l-buten-3-yl)-p-toluidine (111). This reaction was investigated for comparison with the results reported for the 1,2-bis(diphenylphosphino)ethane catalyst system in which the major product resulted from 1,2-addition (32% 111, 8% IV).6 One major limitation of the reactions reported herein appears to relate to steric properties of the dienes. Although terminal dienes appear to undergo this addition reaction quite readily, reaction of aniline with 2,4-hexadiene is extremely sluggish compared to its reaction with 1,3-hexadiene. Furthermore, no amine products were obtained in reactions of diethylamine or piperidine with
I
H-Pd-I
I
dergces nucleophilic attack by the amine to form the amine addition product and regenerate the hydridopalladium iodide catalyst. Support for this mechanism comes in part from the following observations. Tetrakis(tripheny1phosphine)palladium(0) may also be used as a catalyst precursor in these reaction^.^ This is consistent with the proposed initial in situ reduction of the palladium(I1) precursor to a palladium(0) species. Also, tetraethylammonium iodide and tetraethylammonium bromide fail to serve as suitable substitutes for the amine hydroiodide salt indicating the necessity of a source of HI. Further support comes from experiments where the ammonium salts were generated in situ. Diethylamine (11 mmol), isoprene (10 mmol), palladium acetate (0.1 mmol), and triphenylphosphine (0.2 mmol) were combined, 1.0 mmol of concentrated acid was added, and the reaction mixtures were heated at 100-150 “C (21 h). The following yields (GLC, based on isoprene) were obtained for the indicated acid: hydriodic acid, 16% I and 53% 11; hydrobromic acid, 10% I and 18% 11; hydrochloric acid, 6% I and 8% 11. Very poor yields of I (less than 4%) and no I1 were formed with acetic, sulfuric, or phosphoric acid. The poor results with sulfuric and phosphoric acids indicate that an hydridopalladium iodide species and not an hydridopalladium cationic species (“H-Pd+”) is the nec1,4-diphenyl-1,3-butadiene or l-pheny1-3-methyl-l,3-b~- essary catalyst for these reactions. The results of the reactions of aniline with 1,3- and tadiene. A reaction of diethylamine and 1,3,5-cyclo2,4-hexadiene provide evidence for a (vally1)palladium heptatriene was also unsuccessful. intermediate. Addition of the hydridopalladium iodide to A mechanism consistent with experimental evidence is either diene should form the same (vally1)palladium depicted in Scheme I. This involves the in situ reduction complex which after attack by the amine would yield the of the palladium (11) catalyst precursor to a palladium(0) species. Reaction of this complex with HI from the amine hydroiodide salt forms an hydridopalladium iodide species, (9) A reaction of equimolar amounts isoprene and triethylamine using “H-Pd-I”, which acts as the true catalyst. Addition to the 1 mol % (Ph,P),Pd and 10 mol % Et3NH+I-(100 O C , 15 h) yielded 14% diene forms a (r-ally1)palladium complex which then unI and 46% I1 (GLC).
236
Organometallics, Vol. 5, No. 2, 1986
same distribution of products, N-(3-hexen-2-yl)aniline (VI) and N-(2-hexen-4-yl)aniline (VII). The reaction with 1,3-hexadiene produced 45% VI and 4.5% VI1 while the reaction using 2,4-hexadiene produced 30% VI and 2.5% VII. The slight difference in the ratios of VI to VI1 from the two reactions could be due to some reaction of the amine with the initially formed u-palladium complexes.1° Products from the reactions of butadiene and isoprene are believed to consist primarily of the E isomer resulting from reaction of the “H-Pd-I” species with the predominant s-trans conformation of the diene. As support for this, the product from the reaction of diethylamine and 1,3-butadiene was determined to consist primarily of the E isomer (with traces of the 2 isomer) by comparison of its NMR spectrum with those for the pure E and 2 isomers reported in the literature.” Although successful examples of reactions employing primary and secondary aliphatic amines and the aromatic amines aniline and p-toluidine were obtained, no significant quantities of amine products were observed for reactions of ammonia with 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, or 1,3-cyclohexadiene. This is in contrast to reports that ammonia does react with dienes when amine hydroiodide salts are not included in the catalyst s y ~ t e m . This ~ , ~ apparent failure of ammonia to participate in the reactions that include the amine hydroiodide salts suggests that the (x-ally1)palladium complexes in these reactions resemble the r-allyl complexes formed in the reactions of allyl acetates with palladium(0) species (which also do not react with ammonia12) more so than those presumed to be formred in the reactions involving dienes with no amine hydroiodide salt added. Although Scheme I shows this intermediate as a (x-al1yl)palladium iodide, it is indeed possible that this is actually a bis(tripheny1phosphine) (r-allyl palladium cation as the work of Trost13 and Godleski14 indicates to be the case in reactions in which the intermediate is generated from allyl acetates. The fact that 1,2-addition products either are not observed or are obtained in poor yields in reactions involving 1,3-butadiene,isoprene, or 2,3-dimethyl-1,3-butadiene may be explained by the presence of equilibrium processes in which these products are converted to 1,4-addition products. To determine if such a transformation can occur under the reaction conditions, pure N-(l-buten-3-yl)-ptoluidine (111) in a solution of triethylamine to which catalytic quantities of palladium acetate, triphenylphosphine, and triethylammonium iodide had been added was heated at 100 “C. After 9 h, greater than 85% conversion (GLC) to the 1,4-addition product N-(2-buten-ly1)-p-toluidine (IV) had not occurred. As a control, solutions of I11 with each of the three catalyst precursor ingredients alone and in combination with only one of the other ingredients were also heated at 100 “C. No isomerization occurred after 6 days. This isomerization could occur by reaction of a 1,2-addition product with the original amine hydroiodide salt to form an allylammonium salt which could then serve as a suitable precursor for the regeneration of a (x-allylpalladium species by reaction with a palladium(0) complex (10) Akermark, B.; Akermark, G.; Hegedus, L. S.; Zetterburg, K. J . Am. Chem. Soc. 1981,103, 3037. (11) Narita, T.; Inai, N.; Tsurata, T. Bull. Chem. SOC.Jpn. 1973,46, 1242. (12)Trost, B. M.;Keinan, E. J . Org. Chem. 1979,44,3451. (13) Trost, B. M.; Fullerton, T. J. J. Am. Chem. SOC.1973,95,292.(b) Trost, B.M.; Weber, L.; Strege, P. E.; Fullerton, T. J.; Dietsche, T. J. J . Am. Chem. SOC.1978,100, 3416. (14)Godleski, S.A.; Gundlach, K. B.; Ho, H. Y.; Keinan, E.; Frolow, F. Organomptallics 1984, 3, 21.
Armbruster et al. which is in equilibrium with the “H-Pd-I” species. Trost has shown that (x-ally1)palladium complexes can be generated by reactions of allylamines with palladium(0) catalysts in the presence of an acid.15 Also, Hirao has shown that quaternary allylammonium salts react with (phosphine)palladium(O) catalysts to generate (9-allyl)palladium species.16 Furthermore, the palladium-catalyzed positional isomerization of allylamines has been reported, but reaction conditions were not given and no mechanism was proposed.17 Further evidence for the existence of such equilibrium processes comes from studies of reactions of diethylamine with isoprene. Prolonged heating of the reaction mixture described in Table I (1mol % palladium acetate and 2 mol % triphenylphosphine) resulted in little change in the distribution of the products I and 11. However, when the quatities of palladium acetate and triphenylphosphine were increased to 1.5 and 3.0 mol %, respectively (10 mol % triethylammonium iodide), the yields (GLC) of I and I1 after 8 h were 19% and 5670, respectively, but after 28 h had changed to 38% I and 38% 11. In another experiment in which only 1 mol % palladium acetate was used but the quantity of triphenylphosphine was increased to 4 mol 70,the yields of I and I1 were 12% and 5370, respectively, after 15 h but had changed to 30% I and 37% I1 after 84 h. We believe that in the latter two cases, (tripheny1phosphine)palladium species are present in the reaction mixture for a greater length of time and are therefore available to continue the equilibrium processes which cause isomerization of products. The fact that I1 is initially formed in greater yield is consistent with the contention that the allyl moieties of the (a-ally1)palladium intermediates may be interpreted as having cationic properties.16 Thus the (x-ally1)palladiumintermediate that would lead to 11, having tertiary carbonium ion character, is more stable than that which reacts with amine to form I. Since both I and I1 have a trisubstituted double bond, they should be of about the same stability and equilibrium processes can lead to nearly equivalent quantities of the two compounds.
Experimental Section General Comments. All chemicals were used as obtained from commercial sources without further purification. Elemental analyses were obtained from Galbraith Laboratories, Knoxville, TN. Proton NMR spectra were obtained by using a Varian EM-360A NMR spectrometer. GLC yield determinations were obtained by using a Perkin-Elmer Model 900 gas chromatograph (SE-30) with a Cole-Palmer Model 8384-32 recorder with electronic integrator. For preparative GLC purifications, an F&M Model 720 gas chromatograph (SE-52) was used. Triethylammonium iodide was prepared by bubbling hydrogen iodide gas into a solution of triethylamine in ether followed by removal of solvent and unreacted amine under reduced pressure. General Procedure for the Palladium-CatalyzedAddition Reactions of Amines with Conjugated Dienes. (a) Preparative Scale Reactions. The amine (100 mmol), conjugated diene (100 mmol), palladium acetate (1.0 mmol), triphenylphosphine (2.0 mmol), and triethylammonium iodide (10 mmol) were placed in a thick-wall Pyrex reaction bottle containing a magnetic stirring bar. The bottle was flushed briefly with nitrogen and then closed with a neoprene gasket and crown cap. For reactions using 1,3-butadiene, all the reactants but the butadiene were added, the bottle was then flushed with nitrogen, closed, cooled to -78 “C, and evacuated and then the butadiene added (15)Trost, B. M.;Keinan, E. J. O g . Chem. 1980,45,2741. (16)Hirao, T.;Yamada, N.; Ohshiro, Y.; Agawa, T. J . Organomet. Chem. 1982,236,409. (17)Backvall, J.-E.; Nordberg, R. E.; Zetterburg, K.; Akermark, B. Organometallics 1983,2, 1625.
Pd-Catalyzed Additions of Amines to Conjugated Dienes to the preweighed bottle. The reaction mixture was heated with stirring at the indicated temperature (Table I) until the reaction appeared to be complete as determined by GLC (based on the size of the reactant and product peaks). The amine addition product(s) was (were) then obtained by distillation of the reaction mixture. Samples of pure compounds for elemental analyses, NMR spectra, and GLC yield determinations were obtained by either preparative GLC or from center fractions taken during distillation. (b) Reactions in Which Yield Was Determined by GLC. Suitable internal standards were identified (0-xylene or naphthalene) and sensitivity coefficients determined. Reactions generally incorporated from one-twentieth to one-fifth the quantities of amine, diene, and catalyst precursor as used in the preparative reactions. The vessel used in these reactions was either a thick-wall Pyrex tube with a neoprene stopper and crown cap or a Fischer-Porter tube. The reactants plus a known quantity of internal standard were combined, and the tube was closed and heated with magnetic stirring at the indicated temperature (Table I). Yields were determined by GLC at various reaction times by direct injection of aliquots of the reaction mixture. N-(2-Methyl-2-buten-l-yl)-N,N-diethylamine (I): NMR (CDC13) 6 0.98 (t, J = 7 Hz, 6 H), 1.61 (d, J = 6 Hz, 3 H), 1.65 (s, 3 H), 2.42 (9, J = 7 Hz, 4 H), 2.88 (s, 2 H), 5.38 (9, J = 6 Hz, 1 H). Anal. Calcd: C, 76.60; H, 13.48; N,9.93. Found: C, 76.55; H, 13.30; N, 9.74. N-(3-Methyl-2-buten-l-yl)-N,N-diethylamine (11): NMR (CDCl,) 6 1.02 (t,J = 7 Hz, 6 H), 1.67 (s, 3 H), 1.73 (s, 3 H), 2.53 (4,J = 7 Hz, 4 H), 3.05 (d, J = 6 Hz, 2 H), 5.28 (t, J = 6 Hz, 1 H); bp (I and 11,mixture) 62-64 "C (15 mmHg) [lit." bp(I1) 45-47 "C (10 mmHg)]. Anal. Calcd C, 76.60; H, 13.48; N, 9.93. Found C, 76.92; H, 13.65; N, 9.42. N-(2-Buten-l-yl)-N,N-diethylamine: NMR'* (neat) 6 0.90 (t, J = 7 Hz, 6 H), 1.56 (d, J = 3 Hz, 3 H), 2.35 (q, J = 7 Hz, 4 H), 2.90 (d, J = 4 Hz, 2 H), 5.44 (m, 2 H); bp 111-112 "C [lit.6a 57-58 "C (42 mmHg)]. Anal. Calcd: C, 75.52; H, 13.47; N, 11.01. Found: C, 75.81; H, 13.44; N, 10.75. N - (l-Buten-3-yl)-p -toluidine (111): NMR (CDCl,) 6 1.13 (d, J = 6 Hz, 3 H), 2.17 (s, 3 H), 3.20 (s, 1 H), 3.77 (m, 1 H), 4.83-5.23 (m, 2 H), 5.38-5.93 (m, 1 H), 6.33 (d, J = 8 Hz, 2 H), 6.80 (d, J = 8 Hz, 2 H). N-(2-Buten-l-yl)-p-toluidine (IV): NMR (CDC13)6 1.60 (d, J = 3 Hz, 3 H), 2.10 (s, 3 H), 3.27 (s, 1 H), 3.57 (d, J = 3 Hz, 2 H), 5.50 (m, 2 H), 6.40 (d, J = 8 Hz, 2 H), 6.83 (d, J = 8 Hz, 2 H); bp 260 "C (lit.6a260 "C). Samples of I11 and IV (purified by preparative GLC) were also obtained by an alternate synthesis from the reaction of p-toluidine and 3-chloro-1-butene. (18) Trost, B. M . Acc. Chem. Res. 1980, 13, 385.
Organometallics, Vol. 5, No. 2, 1986 237 N-(2,3-Dimethyl-%-buten-l-yl)-N,N-diethylamine (V): NMR (neat) 6 0.96 (t,J = 7 Hz, 6 H), 1.66 (s, 9 H), 2.37 (4, J = 7 Hz, 4 H), 2.89 (s, 2 H); bp 50 "C (12 mmHg) [lit.1963.5-64 "C (16 mmHg)]. Anal. Calcd: C, 77.35; H, 13.63; N, 9.02. Found: C, 77.48; H, 13.46; N, 9.16. N-(2,3-Dimethyl-2-buten-l-yl)-N-butylamine: NMR (CDCl,) b 4.73 (s, 2 H), 0.45-3.38 with significant absorptions at 1.13, 1.65,2.32,3.12(m, 19 H). Anal. Calcd C, 77.35; H, 13.63. Found C, 77.25; H, 13.97. N-(2,3-Dimethyl-2-buten-l-yl)piperidine: N M R (CDC1,) 6 1.42 (m, 6 H); 1.67 (s, 9 H), 2.22 (m, 4 H), 2.73 (s, 2 H); bp 105 "C (28 mmHg) [lit.I953.5-54 "C (2 mmHg)]. Anal. Calcd: C, 78.98; H, 12.65; N, 8.37. Found: C, 79.13; H, 12.49;, N, 8.23. N-(2-Cyclohexeny1)-NJV-diethylamine: NMR (neat) 6 0.88 (t, J = 7 Hz, 6 H), 1.10-2.00 (m, 6 H), 2.30 (q, J = 7 Hz, 4 H), 3.20 (m, 1H), 5.48 (t, 2 H); bp 60 OC (14 mmHg). Anal. Calcd: C, 78.36; H, 12.49; N, 9.14. Found C, 78.22; H, 12.33; N, 9.16. N-(3-Hexen-2-yl)aniline (VI): NMR (CDCl,) b 1.13 (d, J = 6 Hz, 3 H), 1.62 (t, J = 3 Hz, 3 H), 2.13 (d, J = 3 Hz, 2 H), 3.02 (s, 1H), 3.37 (4,J = 6 Hz, 1 H), 5.38 (m, 2 H), 6.45 (m, 3 H), 7.10 (m, 2 H). Anal. Calcd: C, 82.23; H, 9.78; N,7.99. Found: C, 82.14; H, 9.72; N, 8.03. N-(2-Hexen-4-yl)aniline (VII): NMR (CDCl,) 6 0.97 (t, J = 7 Hz, 3 H), 1.63 (s, 1H), 2.02 (m, 2 H), 3.20 (m, 4 H), 5.48 (m, 2 H), 6.58 (m, 3 H), 7.13 (m, 2 H). Anal. Calcd: C, 82.23; H, 9.78; N,7.99. Found: C,82.24, H, 9.60; N, 8.02. A ca. 1O:l mixture of VI and VI1 was reacted with hot alkaline KMnO, followed by acidification and extraction with ether. GLC analysis (Carbowax-2OM) of the organic phase showed the presence of propionic and acetic acids in a ratio of ca. 1O:l. Isomerization of N-(l-Buten-J-yl)-p-toluidine (111) to N-(2-Buten-l-yl)-p-toluidine (IV). A solution of 0.602 g (3.73 mmol) of 111, 0.0224 g (0.1 mmol) of palladium acetate, 0.0524 g (0.2 mmol) of triphenylphosphine, 0.478 g (3.73 mmol) of naphthalene (used as the internal standard) in 1.0 mL of triethylamine was prepared in a thick-wall Pyrex reaction tube. A 0,229-g (1.0-mmol)sample of triethylmmonium iodide was added and the tube closed and heated at 100-105 "C. After 9 h, GLC analysis of the reaction mixture (SE-30) indicated that ca. 86% of I11 had isomerized to IV.
Acknowledgment. Support for undergraduate research participants (R.M.R. and D.L.Z.; summer, 1980) from t h e National Science Foundation is gratefully appreciated. (19) Martirosyan, G. T.; Grigoryan, E. A. Izu. Akad. Nauk Arm. SSR, Khim. Nuuki 1963.16. 31: Chem. Abstr. 1963.59.6354d. (20) Martirosyan, 6.T.;Grigoryan, E. A.; Babayan, A. T . Izu. Akad. Nauk Arm. SSR, Khim. Nauki 1965, 18, 161; Chem. Abstr. 1965, 63, 1468613.
