Cross coupling of magnesium diacetylenides with functional allylic

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We have recently proposed a method for the preparation of 1,4-enynes by the coupling of magnesium diacetylenides with allylic compounds by catalytic ...


UDC 542.97:547.317.8'13:546.46

We have recently proposed a method for the preparation of 1,4-enynes by the coupling of magnesium diacetylenides with allylic compounds by catalytic amounts of nickel complexes activated by Ph3P [i]. In a continuation of these studies and with the aim of developing preparative methods for the synthesis of 1,3-enynes, conjugated diacetylenes, and arylacetylenes, we studied the cross coupling of magnesium diacetylenides with allyl ethers, allyl esters, alkyl halides, allyl halides, aryl halides, allyl sulfides, and allylsulfones. The effect of the nature of the activating additive and the ratio of the catalytic system components on the yield and composition of the cross coupling products was studied in the case of the reaction of diheptynylmagnesium with phenyl ailyl ether. Cu, Zr, Fe, Ni, and Pd compounds in conjunction with phosphorus- and nitrogen-containing ligands were used as catalysts. The maximum yield of l-decen-4->me (I) was achieved upon carrying out the reaction at 50~ for 6 h in THF in the presence of the Ni(acac)2-Ph3P catalytic system taken in 1:4 ratio.

(C~H~C--C-).~Mg+ / - . , _ X _M-L%c ~ c _ - - c _ / ~ TttF


X -= O P h , OAe.

Under these conditions, diheptynylmagnesium and a!lyl acetate give a product mixture consisting of (I), methy!diheptynylcarbinol (II) and 1,4-dipentyl-l,3-diacety!ene (IIi). Table 1 indicates that the selectivity relative to the formation of 1,4-enyne (I) increases with decreasing reaction temperature and reaches 99% at -40~ However, the total yield of (I)-(III) under these conditions does not exceed 10% after 6 h. Independently of the nature of the central atom of the catalyst, the content of (III) does not exceed 4%, while the content of (II) varies from 41 to 94% in a series of Ni, Cu, andPdcompounds. In order to prepare functionally substituted 1,4-enynes and arylacetylenes, we studied the cross coupling of bis(4-ethoxybutynyi)magnesiumwith allylic compounds and iodobenzene leading to 7-ethoxy-l-hepten-4-yne (IV) and 4-ethoxy-l-phenyl-l-butyne (V), respectively. The presence of an oxygen atom in the initial organomagnesium reagent has hardly any effect on the yield and direction of the cross coupling reaction Phl [EtO(CH~)~C~C--]2Mg> EtO(CH2)2C~CPh [Pd]--Pb~ ~\--X--R I [Nil--Ph~P (V) Et0(CH2)2C~C


(IV) + X = O, S, SO~, (C H a)zNI; R = Et, Bu, Ph, CH~=CHCH~--.

A subsequent study of the feasibility of obtaining aryl- and diarylacetylenes by the reaction of bis(phenylethynyl)magnesium with alkyl, allyl, and vinyl halides showed that of the alkyl halides, only alkyl bromides and alkyl iodides react with bis(phenylethynyl)magnesium in the presence of the Ni(acac)2-Ph3P catalyst to give the corresponding l-phenyl-2-aikyl acetylenes (VI) and (VII) in high yields. We note that alkyl halides, independently of the nature of the halide atom, readily react with bis(phenylethynyl)magnesium and are converted to l-phenyl-2-allylacetylene (VIII). In the case of 2-bromostyrene, the greatest activity Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 429-433, February, 1986o Original article submitted August I, 1984.


9 1986 Plenum Publishing Corporation


~o ~D OO

95 100


83 9t 2

55 26 23 22




41 7t 75 77 .


Ph3P (i-C3H~O)3P l(PhO)3PO I(PhO)aP ~ ,~-dipyridyl / w i ~ o u t Ln

t 3 3


4 3 2


Reaction product ratio

*T = 50~ %Catalyst Ni(acac)z:Ln = 1:4.

Ni(acac)2 + 4Ph3P Ni(aoac)a + 4PhsP04 NiC12 + 4PhsP Ca(acacb + 4Ph~P Cu(acac)a + 2Ph3PQ Pd(acac)2 +.4Ph3P


Total Yield~ %


I00 98 9O

Total yield, %









Reaction product ratio (D (H) (HI)


t:4 t:6


i 2




iO0 iO0 t00 iO0 t00

t0 43 55 42





2 2 5 4 3



98 88 52


Total' Reaction product y~eld _ _ ratio

20 50

T., ~G

t0 100



99 68 60 55


3 40

product ratio IReaction Total vield[

TABLE i. Effect of the Nature of nhe Catalyst, Activator, their Ratio, and Temperature on the Yield and Composition of the Cross Coupling of D i h e p t y n y l m a g n e s i u m with Allyl Acetate in THF over 6 h

in the cross coupling with bis(phenylethynyl)magnesium vated by PPha: R--X


X = Br, I

60--80% (PhC~C--)~Mg


X -----CI, Br, I PhCH=CH--Br



is found for palladium complexes actiPhC.--CR

tl = C~H5 (VI); CsHn (VII)


PhC--C--/%, (VIII)

- - ~ ~85%


The Pd(acac)2-PhaP catalyst facilitates the reaction between phenyl halides or bromoanisole and bis(phenylethynyl)magnesium to form 1,2-diphenylacetylene (X) and o-methoxy-l,2diphenylacetylene (XI). These results were used for the synthesis of diacetylenes (XII)(XIV), which were previously difficult to obtain, the cross coupling of bis(phenylethynyl)magnesium or diheptynylmagnesium with 1,3- and 1,4-dibromobenzenes. The yields of (XiI)-(XIV) in all the experiments were in the range from 70 to 82%.


X=Br, I


0 CHa ]8r:

(Ph--C~---C--)2Mg [Pd]

> ~





Ph__C~___C~ C~-C-Ph p - ( X I I ) ; m - (XIII)


-t- (CstlnC--C--)~Mg ---+ C~HnC-- [email protected],,



A study of the reaction of bis(phenylethynyl)magnesium and dialkylmagnesium derivatives with 12 showed that, in the absence of catalyst, the major reaction products are iodoacetylenes, while catalytic amounts of transition metal compounds in conjunction with phosphorusand nitrogen-containing electron-donor ligands facilitate the formation of the corresponding 1,3-diacetylenes (XV)-(XVII!), whose yields depend on the nature of the metal and the !igand structure (Table 2). RC--=CI (RC----C--)2Mg--[__ I~ HC--CC~CH Pd(acac)~--PhaP +

(xv) - (XVIII) I~ = Ph (XV), C~H7 (XVI); C~H9(XVII); C6FIn (XVIII).

A study was then carried out on the reactivity of unsymmetrical mixed organomagnesium reagents containing alkynyl, phenylethynyl, alkyl, and phenyl groups in the cross coupling reaction with allyl ethers. The use of Ni(acac)2-Ph3P as the catalyst gives exclusive formation of 1,4-enynes (I), (VIII), and (XIX) while the corresponding ~-olefins (XX) and (~XI) are obtained in the presence of the Cu(acac)2-Ph3P system. The mixed bimetallic catalyst prepared by Ni)acac)2, Cu(acac) 2 and Ph~P in 0.5:0.5:1 ratio gives a mixture of 1,4-enyne (I), (VIII), and (XIV) and ~-olefin (XX) and (XXI) in equal amounts: Ni(acac)2PhaP


R = CsH~ (XIX), CsHn (1) Ph (VIII)

Cu(acach--Pi%P R ' - - / / ~ RC--C--MgR' + / ~ - - O R " --]~95% R' = Bu (XX), Ph (XXI) Ni(acac)~-- . RC_~C --Cu(acac)~--PhaP,.,


R'= Bu, Ph; R = CaHT, CsHm These results ling reaction with reagents containing

P'h; R"=



tD, (VIII), (XIX)- (xxi)

Et, Bu, Ph, CH2=CH--CH2--.

indicate that the acetylenic fragment more readily enters the cross coupallyl ethers in the presence of nickel complexes in mixed organomagnesium both alkynyl and alkyl or phenyl substituents, while the analogous copper


TABLE 2. Effect of the Catalyst and Activator on the Yield of 1,4-Diphenyldiacetylene (20~ 4 h, THF, M:Ln = I:I) Catalyst* Pd(acac)2 PdC12 PdCl~ - 2CHaCN PdCl2 --Cul

Li2CuCIa Ni (acac) 2

Yield 04 (XV), %] 94 90 83 82 t6 t~

Ni (acac)2 - CuI


Yield of (XV), %

PhsP (PhO) 3P Ph~PO Ph3POr Ph~Sb (EtO) 3P c~, C~-Dzpyridyl

82 54 32 31 26 i6 10"

*In the presence of Ph3P. %PdCI2-CuI as catalyst. catalysts primarily activate the alkyl and aryl groups. This behavior permits us to carry out this reaction with strict selectivity depending on the nature of the catalyst. EXPERIMENTAL The magnesium acetylenides were prepared according to Wotiz [2, 3] and Emptoz [4]. The gas-liquid chromatography was carried out on a Khrom-5 chromatograph with a flame ionization detector using a 1200 • 3 mm column packed with 15% PEG-6000 on Chromatone N-AW. The PMR spectra were taken on a Tesla BS-487B spectrometer for CCI 4 solutions relative to HMDS. The laC NMR spectra were taken on a Jeol FX-90Q spectrometer with wide-band and off-resonance proton suppression in CDCI 3 relative to TMS. The IR spectra were taken neat on a UR-20 spectrometer. The mass spectra were taken on an MKh-13-06 mass spectrometer with 70 eV ionization energy and 200~ ionization chamber temperature. General Procedure for the Cross Coupling of Magnesium Diacetylenide_s with Ally~ic Compounds A sample of 20 ml (20 mmole) of 1 M magnesium diacetylenides in THF was added with stirring in an argon stream to a solution of 1 mmole transition metal compound in THF, 4 mmole activator ligand, and 35 mmole of the corresponding allylic compound at --5~ and the reaction mass was maintained at this temperature for about I0 min. The solution was transferred to a thermostatted glass reactor and heated for 4-6 h at 40-60~ At the end of the reaction, the catalysate was decomposed with saturated aqueous NH~CI, extracted with ether, washed with aq. NaHNO 3 and then water until neutral. The ethereal solution was dried over MgS04. After distilling of the solvent, the residue was distilled in vacuum. General Procedure for the Cross Coupling of Magnesium Diacetylenides A I ~ I and Aryl Halides A sample of 40 ml (40 mmole) 1 M magnesium diacetylenides in THF was added in an argon stream to a solution of 1 mmole Ni or Pd compound, 2 mmole Ph3P and 70 mmole of the corresponding alkyl or aryl halide in THF at -5~ and the reaction mass was maintained at this temperature for about 15 min. The solution was transferred to a thermostatted reactor and heated for 4 h at 40~ At the end of the reaction, the catalysate was treated by the ordinary workup procedure. Reaction of Magnesium Diacetylenides with 12 A sample of 50 mmole 12 was added to a solut$on of 1 mmole transition metal compound, 1 mmole activator ligand in THF, and 50 ml 1 M solution of the corresponding magnesium diacetylenides in THF in an argon stream at -40~ The mixture was warmed to about 20~ and maintained for 4 h. The catalysate was treated by the ordinary work-up procedure. The compounds obtained had the following constants. 7-Ethoxy-l-hepten-4-yn e (IV), bp 53-54~ (2 mm), nD 2~ 1.4470. IR spectrum (~, cm-i): 920, 1000, 1650, 3085. PMR spectrum (6, ppm): 1.08 t (3H, CH3), 2.08-2.50 m (2H, ~C-CH2), 2.67-2.92 m (2H, ~CCH2C=), 3.17-3.63 m (4H, OCH2), 4.75-6.00 m (3H, CH2=CH-), 13C NMR spectrum (6, ppm): i15.64 t (CI), 133.09 d (C2), 23.12 t (C3), 79.36 s (C~), 77.69 s (C5), 20.85 t (C6), 69.24 t (C7), 66.25 t (C8), 15.13 q (C9). M + 138.


4-E~Ihen l-l-but e (V), bp 77-78~ (2 mm). IR spectrum (v, cm-~): 700, 765, 1600~ 2230. PMR spectrum (6, ppm): 1.13 t (3H, Ch3), 2.55 t (2H, ~CCH2-), 3.20--3.70 m (4H, OCH~), 7.00-7.50 m (SH, aromat. H). M + 174. o-__Methoxy-l,2~t, l ~ q e(XI__), bp 172-173~ (i n~). nD 2~ 1.6575. IR spectrum (~, cm-i): 760, 1500, 1575, 1600. PMR spectrum (~, ppm): 3.83 s (3H, CH~), 6.63-7~ m (gH, aromat. H)o M + 208. 1590.

l,Z-Bis(diph~'l)benzene PMR spectrum (6, ppm): 7~

(XIII), mp i03-_05 C. IR spectrum (v, cm-l): 680, 750, m (14H, aromat. H)o M + 278.

1,4-B~nyl)benzene (XIV), bp 131-142~ (i ~n). IR spectrum (~, cm'~): 845, 1510. PMR spectrum (6, ppm): 0.92 t (3H, CH3), 1.17-1.80 m (12H, CH~), 2.17-2.58 m (4H, eC-CH2), 7.25 m (4H, aromato H). M + 266. l-Octen-4-~, bp 44-45~ (20 mm), nD 2~ 1.4435. IR spectrum (v, cm-i): 920, i000, 1650, 3030, 3090. PMR spectrum (6, ppm): 0~91 t (3H, CH3), 1.13-1.80 m (2H, CH2), Io87-2.25 m (2H, ~C-CH2), 2.67-2.92 m (2H, ~C-CH2-C=), 4.80-6.08 m (3H, CH2=CH-). M* 108. Products (i)-(III), (VI)-(X), (XII), (XV), and (XVIII) were identified by comparison with authentic samples [5-9]. CONCLUSIONS An efficient method has been developed for the synthesis of 1,4-enynes, conjugated acetylenes and aryl acetylenes by the cross coupling of magnesium diacetylenides with allyl ethers and esters, alkyl halides, allyl halides, aryl halides, a!lyl sulfides, andallylsulfones, using Ni and Pd complexes as the catalyst. LITERATURE CITED i. ,

3. 4. 5. 6. 7. 8. 9.

U. M. Dzhemilev, Ao G. Ibragimov, R. A. Saraev, and Do Lo Minsker, Izvo Akado Nauk SSSR, Set. Khimo, 907 (1984). J. H. Wotiz, C. A. Hollingsworth, and R. Eo Dessy, Jo Amo Chemo Soc., 78, 1221 (1956). J. H. Sotiz, C. A. Hollingsworth, and R. E. Dessy, J. Org. Chem., 21, 1063 (1956). Go Emptoz and F. Huet, J. Organometal. Chem., 8~2, 139 (1974). H. K. Black, D. H. S. Horn, and B. C. L. Weedon, J. Chem. Soc., 1704 (1954). V. Grignard, Comptes Rend~ Acad. Sci., 357 (1929). J. P. Danehy, D. Bo Killian, and J. A. Nienwland, J. kmo Chem. Soco, 58, 61] (.9~6) J. P. Bert, Po C. Dorier, and R. Lamy, Comptes Rend. Acad. Sci., 555 (1925). M. T. Bogert and D~ Davidson, J. Am. Chem, Soc., 54, 334 (1932).