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Barbier-type allylation of carbonyl compounds and imines with metallic cadmium
Tekahednm Letters. Vol. 33. No. 33. pp. 4795-4198.1992 Printedin Great Britain
Barbier-Type
0040-4039,92 $5.00 + .00 Pergamon Press Ltd
Allylation of Carbonyl Compounds with Metallic Cadmium
and Imines
Bir Sain, Dipak Prajapati and Jagir S Sandhu* Regional Research Laboratory, Jorhat 785 006, India
Abstract
: Cadmium
mediated allylation of a variety of carbonyl compounds and imines in a Cd/Bu4NBr/THF system afforded excellent yields of the corresponding homoallylic alcohols and amines under very mild reaction conditions.
There has been growing interest in the use of metallic elements in synthetic chemistry and various metals have 2been successfully used for Barbier-type allylation of carbonyl compounds ’ . Allylation of imines with various ally1 metals like ally1 boronates, allyl-9-BBN, ally1 stannanes, ally1 magnesiy, ally1 zinc compounds and ally1 lead reagents has also been reported . In condinuation of our studies on metal catalysts, we would likq to report here the first examples .of metallic Cd/Bu4NE!r system promoted Barbier type allylation of carbonyl compounds and immes, which proceed smoothly under very mild conditions’ to afford homoallylic alcohols and amines in excellent yields in a regio-specific manner. In a typical procedure (entry l), t$ a suspension of cadmium powder (247mg, 2.2 mmol), in dry tetrahydrofuran (4ml) was added Bu4NBr (709mg, 2.2 mmol) followed by addition of a mixture of ally1 bromide (366mg, 3 mmol) and benzaldehyde (212mg, 2 mmol). The reaction mixture was
Y I-I
R’ R2vX+~~~=
X=Br,l,
y
Cl
Y=O,N
C*djBur,
NBrlTHF
R3
stirred at room temperature for 4h and then was quenched by addition of dilute hydrochloric acid. The product was extracted with ether and purified by column chromatography on silica gel to afford I-phenyl-3-buten-l-01 (266mg, yield 90%). Other results for carbonyl compounds and imines are summarized in the Table.
4795
4796
Table:
Entry
Cadmium
metlintcd
Ally1 halide
allylotion
Carbonyl
of cnrhonyl
compound
c$-itjc Ho
1
nntl iminesa.
Pro&c
t
C6H5yQ
-Oh
_CHO 2
C6H5CH =CH-C,YO
3
compounds
c6ti5cti=cH
Time(h)
90
4
70
4
94
5
93
4
60
12
79
6
91
8
95c
4
OH
C6H 5CH=CH-COC%
4
yieldb
c 6H 5cH=CHbc@ 5
J-4
6
COOC2 H 5
/&%OOcD:H,
FCHO C6H 5COCH3
7
CSHi&@ OkI OH
C6H5CH0
8
+c6H5 _CHO
9
5
24
7!jd
10
HOOH ,,,/,/JHO
10
de
C6H 5CH = NC6H5
II
yHCGH5
90
4
60
I2
‘gH? CH2C6H5
12
a All reactions were carried out in the same manner as text and disappearance of starting material was monitored b Based on carbonyl compound/imine ’
Erythro:threo=70:30
d Acetylene:allene=64:36
described by TLC.
in
the
4791
and virtually no The effect of Bu NBr was found to be remarkable Roughly one equivalent of 13u4NBf was allylatlon occurred in I4 s absence. found to be sufficient for these reactions and use of a large excess did “fat help either to get higher yields or better reaction rates. Use of other salts like NaBr, KBr, MgBr2 and LiC104 in place of Bu NBr was found to be Ally1 iodide was fou%d equally reactive to ineffective, giving no reaction. ally1 bromide, but the reactivity of ally1 chloride was found to be much less. aldehydes and imines could be allylated in high Various types of ketones, yields, while esters and cyano groups were not affected under the reactlon conditions. Even substrates having active hydrogen like ethylacetoacetate (entry 5) could be readily allylated in good yields. The allylation was found to be highly regiospecific; allylic halides reacted only at the V-position and @unsaturated carbonyl compounds and imines gave reglospeclflc 1,2-addition products. Allylation of benzaldehyde with crotyl bromide afforded a mixture of erythro and threo alcohols in the ratio 70:30. Allylation of octyl aldehyde with propargyl bromide gave a mixture of the acetylenic and allenic products in the ratio 64:36. Although the detailed mechanism of this reaction is not clear, it is likely that Bu4NBr effects the generation of an active qrganocadmium reagent. A similar effect has been reported in the case of lead Cadimum mediated synthetic reactions have been scarcely studied6 the present allylation of carbonyl compounds and imines is remarkable regard to its generality, high yields and mildness of reaction conditions.
Acknowledgement: The authors are division of this laboratory for spectral
References
thankful analyses.
to
the
analytical
and with
chemistry
and Notes
1.
(a) Tanaka, H.; Hamatani, T.; Yamashita, S.; Torii, S. Chem. Lett. 1986, 1461 and re’ferences cited therein. (b) Wada, M.; dkhi, H.; Akiba, K.-Y. Tetrahedron Lett. 1986, z, 4771. (c) Butsugan, Y.; Ito, H.; Araki,. S. Tetrahedron Lett. 1987, 2, 3707. (d) Imamoto, T.; Kusumoto, T.; Tawarayama, Y.; Sugiura, Y.; Mita, T.; Hatanaka, Y.; Yokoyama, M. L Org. Chem. 1984, s, 3904-39 12. (e) Patrier, C.; Luche, J. L. J. Org. Chem. 1985, so, 910. (f) Zhu; L.; Wehmeyer, R.M.; Rieke, R.D. J. Org. Chem. 1991, 5& 1445. (g) Araki, S.; Katsumurs, N.; Ito, H.; Butsugan, Y. Tetrahedron Lett. 1989, 2, 1581. (h) Li, C.J.; Chan, T.H. Tetrahedron & 1991, 2, 7017. (i) Oda, Y.; Matsuo, S.; Saito, K. Tetrahderon Lett. 1992, 3, 97.
2.
For some more recent contributions see: Shono, T.; Ishifune, M.; Kashimura, S. Chem. Lett. 1990, 449 and references cited therein. For SbCl -Fe see. Wang, W. -B.; Shi, L. L.; Huang, Y.-Z. Tetrahedron, 1990 3, 3315; For Ba see: Yanagisawa, A.; Habaue, S.; Yamamoto, Ii. J. Am.
4798
Chem. Sot. 1991, 113, 8955; Sm is a recent favourite see: Kondo, T.; Akazome, M.; Watanabe, Y. J. Chem. Sot. Chem. Commun. 1991, 757. For a review see: Molander, G. A. Chem. Rev., 1992, & 29; For use of iron complexes see: Jiang, S.; Turos, E. Tetrahedron Lett. 1991, G 4639. For CrCl method see Cintas, P. Synthesis. 1992, 248. For allylic acetates using Pd($Ph ) -Zn see: Masuyama, Y.; Kinugawa, N.; Kurusu, Y. J. Org. Chem., 1987, %d, 3702. (a) Keck, G.E.; Enholm, E. J. J. Org.. Chem. 1985, so, 146. (b) Yamamoto, Y.; Nishii, S.; Maruyama, K;; Komatsu, T.; Ito, W. J. Am. Chem. Sot., 1986, 108, 7778. (c) Tanaka, H.; Yamashits, S.; Ikamoto, Y.; Torii, S. Chem. Lett., 1987, 673. (d) For, two recent reports on the allylation of lmlnes wlth ally] fluorosilanes and ally] cuprates see: Kira, M.; Hino, T.; Sakurai, H. Chem. & 1991, 277 and Bocoum, A.; Boga, C.; Savoia, D.; Umani Ronchi, A. Tetrahedron Lett. 1991, G 1367. Araki,,S.; Butsugan, Y.; Ito, H. J. Organomet. Chem. 1988, 347, 5. Abenheim D.; Henry-Basch, E.; Freon, I’. Bull. Sot. Chim. Fr., 1969, 4038. Courtols, G.; Miginiac, L. J. Organomet. Chem. 1974, Krl-44. le,h,i , the Despite reports of similar chemistry working in aqueous systems use of aqueous tetrahydroguran in place of dry tetrahydrofuran solvent in these reactions gave poor yields of the desired homoallylic alcohols and amines. For a related report see: Waldmann, H. Liebigs Ann. Chem. 1991, 1317. For rare reports on the use of cadmium inorganic synthesis E.R.; Rieke, R.D. J. Org. Chem. 1985, 50, 416 and references
(Received in UK 11 June 1992)
see: Burkhardt, cited therein.
Barbier-Type
0040-4039,92 $5.00 + .00 Pergamon Press Ltd
Allylation of Carbonyl Compounds with Metallic Cadmium
and Imines
Bir Sain, Dipak Prajapati and Jagir S Sandhu* Regional Research Laboratory, Jorhat 785 006, India
Abstract
: Cadmium
mediated allylation of a variety of carbonyl compounds and imines in a Cd/Bu4NBr/THF system afforded excellent yields of the corresponding homoallylic alcohols and amines under very mild reaction conditions.
There has been growing interest in the use of metallic elements in synthetic chemistry and various metals have 2been successfully used for Barbier-type allylation of carbonyl compounds ’ . Allylation of imines with various ally1 metals like ally1 boronates, allyl-9-BBN, ally1 stannanes, ally1 magnesiy, ally1 zinc compounds and ally1 lead reagents has also been reported . In condinuation of our studies on metal catalysts, we would likq to report here the first examples .of metallic Cd/Bu4NE!r system promoted Barbier type allylation of carbonyl compounds and immes, which proceed smoothly under very mild conditions’ to afford homoallylic alcohols and amines in excellent yields in a regio-specific manner. In a typical procedure (entry l), t$ a suspension of cadmium powder (247mg, 2.2 mmol), in dry tetrahydrofuran (4ml) was added Bu4NBr (709mg, 2.2 mmol) followed by addition of a mixture of ally1 bromide (366mg, 3 mmol) and benzaldehyde (212mg, 2 mmol). The reaction mixture was
Y I-I
R’ R2vX+~~~=
X=Br,l,
y
Cl
Y=O,N
C*djBur,
NBrlTHF
R3
stirred at room temperature for 4h and then was quenched by addition of dilute hydrochloric acid. The product was extracted with ether and purified by column chromatography on silica gel to afford I-phenyl-3-buten-l-01 (266mg, yield 90%). Other results for carbonyl compounds and imines are summarized in the Table.
4795
4796
Table:
Entry
Cadmium
metlintcd
Ally1 halide
allylotion
Carbonyl
of cnrhonyl
compound
c$-itjc Ho
1
nntl iminesa.
Pro&c
t
C6H5yQ
-Oh
_CHO 2
C6H5CH =CH-C,YO
3
compounds
c6ti5cti=cH
Time(h)
90
4
70
4
94
5
93
4
60
12
79
6
91
8
95c
4
OH
C6H 5CH=CH-COC%
4
yieldb
c 6H 5cH=CHbc@ 5
J-4
6
COOC2 H 5
/&%OOcD:H,
FCHO C6H 5COCH3
7
CSHi&@ OkI OH
C6H5CH0
8
+c6H5 _CHO
9
5
24
7!jd
10
HOOH ,,,/,/JHO
10
de
C6H 5CH = NC6H5
II
yHCGH5
90
4
60
I2
‘gH? CH2C6H5
12
a All reactions were carried out in the same manner as text and disappearance of starting material was monitored b Based on carbonyl compound/imine ’
Erythro:threo=70:30
d Acetylene:allene=64:36
described by TLC.
in
the
4791
and virtually no The effect of Bu NBr was found to be remarkable Roughly one equivalent of 13u4NBf was allylatlon occurred in I4 s absence. found to be sufficient for these reactions and use of a large excess did “fat help either to get higher yields or better reaction rates. Use of other salts like NaBr, KBr, MgBr2 and LiC104 in place of Bu NBr was found to be Ally1 iodide was fou%d equally reactive to ineffective, giving no reaction. ally1 bromide, but the reactivity of ally1 chloride was found to be much less. aldehydes and imines could be allylated in high Various types of ketones, yields, while esters and cyano groups were not affected under the reactlon conditions. Even substrates having active hydrogen like ethylacetoacetate (entry 5) could be readily allylated in good yields. The allylation was found to be highly regiospecific; allylic halides reacted only at the V-position and @unsaturated carbonyl compounds and imines gave reglospeclflc 1,2-addition products. Allylation of benzaldehyde with crotyl bromide afforded a mixture of erythro and threo alcohols in the ratio 70:30. Allylation of octyl aldehyde with propargyl bromide gave a mixture of the acetylenic and allenic products in the ratio 64:36. Although the detailed mechanism of this reaction is not clear, it is likely that Bu4NBr effects the generation of an active qrganocadmium reagent. A similar effect has been reported in the case of lead Cadimum mediated synthetic reactions have been scarcely studied6 the present allylation of carbonyl compounds and imines is remarkable regard to its generality, high yields and mildness of reaction conditions.
Acknowledgement: The authors are division of this laboratory for spectral
References
thankful analyses.
to
the
analytical
and with
chemistry
and Notes
1.
(a) Tanaka, H.; Hamatani, T.; Yamashita, S.; Torii, S. Chem. Lett. 1986, 1461 and re’ferences cited therein. (b) Wada, M.; dkhi, H.; Akiba, K.-Y. Tetrahedron Lett. 1986, z, 4771. (c) Butsugan, Y.; Ito, H.; Araki,. S. Tetrahedron Lett. 1987, 2, 3707. (d) Imamoto, T.; Kusumoto, T.; Tawarayama, Y.; Sugiura, Y.; Mita, T.; Hatanaka, Y.; Yokoyama, M. L Org. Chem. 1984, s, 3904-39 12. (e) Patrier, C.; Luche, J. L. J. Org. Chem. 1985, so, 910. (f) Zhu; L.; Wehmeyer, R.M.; Rieke, R.D. J. Org. Chem. 1991, 5& 1445. (g) Araki, S.; Katsumurs, N.; Ito, H.; Butsugan, Y. Tetrahedron Lett. 1989, 2, 1581. (h) Li, C.J.; Chan, T.H. Tetrahedron & 1991, 2, 7017. (i) Oda, Y.; Matsuo, S.; Saito, K. Tetrahderon Lett. 1992, 3, 97.
2.
For some more recent contributions see: Shono, T.; Ishifune, M.; Kashimura, S. Chem. Lett. 1990, 449 and references cited therein. For SbCl -Fe see. Wang, W. -B.; Shi, L. L.; Huang, Y.-Z. Tetrahedron, 1990 3, 3315; For Ba see: Yanagisawa, A.; Habaue, S.; Yamamoto, Ii. J. Am.
4798
Chem. Sot. 1991, 113, 8955; Sm is a recent favourite see: Kondo, T.; Akazome, M.; Watanabe, Y. J. Chem. Sot. Chem. Commun. 1991, 757. For a review see: Molander, G. A. Chem. Rev., 1992, & 29; For use of iron complexes see: Jiang, S.; Turos, E. Tetrahedron Lett. 1991, G 4639. For CrCl method see Cintas, P. Synthesis. 1992, 248. For allylic acetates using Pd($Ph ) -Zn see: Masuyama, Y.; Kinugawa, N.; Kurusu, Y. J. Org. Chem., 1987, %d, 3702. (a) Keck, G.E.; Enholm, E. J. J. Org.. Chem. 1985, so, 146. (b) Yamamoto, Y.; Nishii, S.; Maruyama, K;; Komatsu, T.; Ito, W. J. Am. Chem. Sot., 1986, 108, 7778. (c) Tanaka, H.; Yamashits, S.; Ikamoto, Y.; Torii, S. Chem. Lett., 1987, 673. (d) For, two recent reports on the allylation of lmlnes wlth ally] fluorosilanes and ally] cuprates see: Kira, M.; Hino, T.; Sakurai, H. Chem. & 1991, 277 and Bocoum, A.; Boga, C.; Savoia, D.; Umani Ronchi, A. Tetrahedron Lett. 1991, G 1367. Araki,,S.; Butsugan, Y.; Ito, H. J. Organomet. Chem. 1988, 347, 5. Abenheim D.; Henry-Basch, E.; Freon, I’. Bull. Sot. Chim. Fr., 1969, 4038. Courtols, G.; Miginiac, L. J. Organomet. Chem. 1974, Krl-44. le,h,i , the Despite reports of similar chemistry working in aqueous systems use of aqueous tetrahydroguran in place of dry tetrahydrofuran solvent in these reactions gave poor yields of the desired homoallylic alcohols and amines. For a related report see: Waldmann, H. Liebigs Ann. Chem. 1991, 1317. For rare reports on the use of cadmium inorganic synthesis E.R.; Rieke, R.D. J. Org. Chem. 1985, 50, 416 and references
(Received in UK 11 June 1992)
see: Burkhardt, cited therein.