Journal of Molecular Catalysis, 85 (1993) L117-L119 Elsevier Science Publishers B.V., Amsterdam

L117

A new double carbonylation reaction

Ibrahim Amer* Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); e-mail: AMERBBGUMAZL. BGU.AC.ZL

Howard Alper Department of Chemistry University of Ottawa, Ottawa, Ontario KIN 6N5 (Canada)

(Received April 20,1993; accepted August 25,1993)

Abstract

The phase transfer catalyzed carbonylation of a-vinylcinnamic acid to an a-ketolactone in the presence of nickel cyanide is the first example of a decarboxylation-double carbonylation reaction.

Key words: carbonylation; cyanide, nickel, phase transfer catalysts

In a previous study one of us described the double carbonylation of 2- bromo-1-phenyl-1,3-butadiene (1) to the 4-benzyl-5-methyL2,3dihydrofur- ane-2,3-dione (2) and to a-vinylcinnamic acid (3) (eq. 1 ), catalyzed by Ni ( CN)2-4H20 and phase transfer catalysts [ 11. One of the mechanistic path- ways leading to the double carbonylation product is a stepwise process, in which 1 is first converted to 3, and the latter leads to 2.

+ latm) Ni(CN)2.4H,0,

5N NaOH. SO’C

0

communication describes first example the double of a acid leading the novel of unsaturated derivatives.

The system was by treatment nickel cyanide (1 mmol) and tetradecyltrimethylammonium bromide (0.2 mmol) in 6.25 M NaOH (20 ml) and toluene (15 ml) with carbon monoxide for 1 h at 95’ C. The acid 3 (6 mmol, readily obtained from crotonic anhydride and benzalde-

*Corresponding author.

0304-5102/93/$06.00 0 1993 - Elsevier Science Publishers B.V. All rights reserved.

L118 I. Amer, H. Alper / J. Mol. Catal. 85 (1993) L117-L119

hyde) [2] in 10 ml of toluene was added over a period of 1 h and stirring was continued for an additional 4 h. Cooling, separation and acidification (10% HCl) of the aqueous phase gave the a-ketolactone (2) as the only product in 69 % yield*.

It seems that the temperature has a remarkable effect on the decarboxyl- ation-carbonylation reaction (Table 1). While a temperature of 95°C gave a good catalytic reaction, temperatures higher than 100°C or lower than 70°C afforded no carbonylation products. While very high temperatures may cause polymerization of the diene and for decomposition of the catalytic intermedi- ate, as was shown in the case of other carbonylation reactions catalysed by Ni(CN)z [3], low temperatures did not allow the first step of the catalytic decarboxylation. The basicity of the aqueous phase also has an influence on the carbonylation reaction with 6.25 M NaOH being better than 5 M. Replace- ment of cY-vinylcinammic acid by propylenecinammic acid (2-benzylidene-3- pentenoic acid) gave only 30% of double carbonylation product, and 1,3-cy- clooctadiene-2carboxylic acid gave no double carbonylation product.

A possible mechanism for the conversion of 3 to 2 is outlined in Scheme 1. Reaction of 3 with the catalytic species Ni (CO), CN- may give the carbox- ylate complex 4. Decarboxylation of 4 will lead to the a-alkenylnickel complex (6) [4] which can be converted to the metallacycle 7 by carbonylation (via 6) and ligand exchange under CO and heat conditions. Steps 5 to 8 of Scheme 1 were confirmed in the case of double carbonylation of halodienes, in which we proposed by electronic and steric effects. Temperatures less than 70’ C gave only mono carbonylation products and steric hindrance on the vinyl group cause reduction in the double carbonylation products (e.g., 2-bromo-l-phenyl- 4-methyl-1,3-pentadiene gave only mono carbonylation product even at 100” C)

TABLE I

Double carbonylation of a-vinylcinnamic acid catalyzed by Ni(CN),-4H,O and phase transfer catalystsa

Temperature

(“C) NaOH

(M)

Conversion

(%)

Yield of

2 (%)

72 6.25 12 5 95 6.25 100 69

115 6.25 Sob 20 95 5 63 42

Vkaction conditions: substrate (6.0 mmol) in toluene (10 ml), Ni( CN)z*4Hz0 (1.0 mmol), aqueous base (20 ml), tetradecyltrimethylammonium bromide (0.2 mmol), toluene ( 15 ml), CO (1 atm), 95°C. b30% of dihydro cu-vinylcinnamic acid was also isolated.

*Compared to authentic samples by NMR, IR and mass spectra.

I. Amer, H. Alper / J. Mol. Catal. 85 (1993) Lll 7-L119 L119

co I -Ni(CO)&N

Scheme 1.

[ 51. Then, 9 can be obtained from 7 by attack of base to form 8, decomplex- ation resulting in regeneration of the catalytic species Ni (CO)&N-. Acid in- duced cyclization of 9 would then afford 2 after acidification of the aqueouse phase.

In conclusion, nickel cyanide and phase transfer catalyzed carbonylation of a-vinylcinnamic acid to an a-ketolactone, is the first example of a decar- boxylation-double carbonylation reaction. Detailed studies are in progress; the results of the carbonylation of the labelled acid 3 will be published in due course.

Acknowledgement

This work was supported by the Israeli Ministry of Science and Technol- ogy through Grant No. 3294190.

References

H. AIper and G. Vasapollo, Tetrahedron Lett., 30 (1989) 2617. R. Kuhn and S. Ishikawa, Ber. Chem., 9 (1931) 2347. I. Amer and H. Alper, J. Organomet. Chem., 383 (1990) 573. The decarboxylation of carboxylic acids by transition metal salts and heat is widely used in synthesis. G.B. Deacon, S. J. Faulks and G.N. Pain, in F.G.A. Stone and R. West (eds.), Ad- vances in Organometahic Chemistry. Wiley, New York, 1986, Vol. 3; pp. 237-270. K. Younis, I. Amer, H. Alper, in preparation.