(Hive Addict)
03-07-03 09:44
No 414620
(Rated as: excellent)
The text has been taken over from the following reference: Sasmita Das, AK Panigrahia, GC Maikapb. NaIO4–DMF: a novel reagent for the oxidation of organic halides to carbonyl compounds. Tetrahedron Letters 44 (2003) 1375-1377.
Abstract - NaIO4–DMF oxidises various primary and secondary halides to the corresponding aldehydes and ketones under mild conditions (150°C/40–60 min) in high yields (70–90%).
Introduction - Oxidation of organic halides to the corresponding carbonylcompounds is a well known transformation in organic synthesis. In 1949, the Hass–Bender reaction was reported for the oxidation of halides.1 Several methods have been developed to carry out this conversion 2,3 such as the Sommelet reaction 4 which is limited to benzylic halides, the Krohnke reaction (pyridine followed by p-nitrosodimethylaniline) 55 and the Kornblum reaction (DMSO/NaHCO3) 6 which is limited to active halides and requires very high temperature. Various amine N-oxides 7-9 are also used for this oxidation. Masaki et al. 10 have reported the photooxidation of aryl bromides with mesoporous silica FSM-16. More recently, 2-dimethylamino-N,N-dimethyl aniline-N-oxide 11 was used for this conversion in high yield. All the above procedures are limited and required high temperatures. To circumvent all these obstacles, we planned to explore the use of NaIO4–DMF for the oxidation of halides to the corresponding carbonyl compounds. We wish to report here a new and convenient method for the preparation of aldehydes and ketones from the corresponding halides.
The importance of sodium metaperiodate in organic synthesis prompted us to examine the behaviour of sodium metaperiodate and dimethyl formamide on different halogen compounds. Primary and secondary halides were reacted with NaIO4–DMF to give the corresponding aldehydes and ketones, respectively. It was found that different primary halides (Table 1) and secondary halides (Table 2) gave the corresponding carbonyl compounds in good yields in short time periods. Octyl bromide was converted into octanal in an 85% yield (Table 1, entry 1). Benzyl bromide (entry 2) and a substituted benzyl bromide (entry 3) gave the corresponding aldehydes in good yields. Different halomethyl naphthalenes (entries 4, 5 and 6) were also converted to the corresponding aldehydes in 80–85% yields. Cinnamyl bromide and chloride (entries 7 and 8) also gave cinnamaldehyde in 90 and 84% yields in 50 and 55 min, respectively.
Secondary halides gave the corresponding ketones, as shown in Table 2. For example, cyclohexyl bromide (Table 2, entry 1) gave cyclohexanone in an 84% yield. Bromodiphenyl methane was converted to benzophenone in 90% yield and chlorodiphenyl methane (Table 2, entry 3) took a little more time but gave benzophenone in 80% yield. 9-Bromofluorene (Table 2, entry 4) give 9-fluorenone in good yield in 45 min.
The behaviour of this reagent towards the alfa-halocarbonyl compounds, i.e. phenacyl bromide was also examined, but to our surprise benzaldehyde was isolated instead of phenyl glyoxal. Phenacyl bromide might have undergone the same oxidation (Scheme 1) as primary halides to give phenyl glyoxal which is further oxidized to phenylglyoxalic acid which undergoes decarboxylation to give benzaldehyde (85% yield based upon GC–MS).
In conclusion, we have developed a new method to convert primary and secondary halides to the corresponding aldehydes and ketones, using for the first time the oxidising property of a mixture of NaIO4 and DMF.
Typical reaction procedure - Benzyl bromide (0.34 g, 2 mmol) was taken in a round bottom flask along with sodium metaperiodate (NaIO4) (0.42 g, 2 mmol). The above mixture was dissolved in 30 ml of N,N-dimethyl formamide (DMF). The reaction mixture was heated at reflux. The progress of the reaction was monitored by thin layer chromatography by comparison with the starting material (10% ethyl acetate in hexane). The reaction was completed in 40 min. The reaction mixture was cooled and treated with 20 ml of water and then extracted with ether (2×30 ml). The combined ether layers were dried over anhydrous magnesium sulphate (MgSO4), then filtered off and concentrated. GLC analysis of the reaction mixture showed the presence of benzaldehyde (80%). Purification by column chromatography on 60–100 mesh silica gel gave (0.18 g, 80%) of benzaldehyde. The formation of benzaldehyde was further confirmed by the melting point of its 2,4-dinitrophenylhydrazone derivative.
Schemes 1 and 2
NaIO4/DMF
R-X ---------------------> R-CHO
(R=Cl, Br) 150°
------------------------------------------------ ---
ENTRY SUBSTRATE PRODUCT TIME YIELD(%)
1 C8H17Br C8H16O 46 85
2 PhCH2Br PhCHO 40 80
7 PhCHCHCH2Br PhCHCHCHO 50 90
8 PhCHCHCH2Cl PhCHCHCHO 55 84
NaIO4/DMF
R2CHX ---------------------> R2CO
(R=Cl, Br) 150°
------------------------------------------------ ---
ENTRY SUBSTRATE PRODUCT TIME YIELD(%)
2 Ph2CHBr Ph2CO 45 90
3 Ph2CHCl Ph2CO 50 80
Acknowledgements - We wish to thank the U.G.C. (New Delhi) for generous financial support.
References
1. Hass, H. B.; Bender, M. L. J. Am. Chem. Soc. 1949, 7, 1767–1769.
2. Kileny, S. N. In Comprehensive Organic Synthesis; Trost, B. M.; Ley, S. V., Eds.; Pergamom Press: Oxford, 1991; Vol. 7, pp. 653–670.
3. Smith, M. B.; March, J. March ’s Advanced Organic Chemistry, 5th ed.; Wiley-Interscience Publication: New York, 2001; pp. 1535–1536.
4. Larock, R. C. Comprehensive Organic Transformations; VCH Publication: NewYork, 1989; pp. 599–600.
5. Krohnke, F. Angew. Chem., Int. Ed. 1963, 2, 380–393.
6. Kornblum, N.; Jones, W. J.; Anderson, G. J. J. Am. Chem. Soc. 1959, 81, 4113.
7. Franzen, V. Org. Synth. 1973, 5, 872–874.
8. Mukaiyama, S.; Inanga, J.; Yamaguchi, M. Bull. Chem. Soc. Jpn. 1981, 54, 2221.
9. Suzuki, S.; Onishi, T.; Fujita, Y.; Misawa, H.; Otera, J. Bull. Chem. Soc. Jpn. 1986, 59, 3287.
10. Itoh, A.; Kodana, T.; Inagaki, S.; Masaki, Y. Org. Lett. 2000, 2, 2455–2457.
11. Chandrasekhar, S.; Sridhar, M. Tetrahedron Lett. 2000, 41, 5423–5425.
Abusus non tollit usum
(Hive Bee)
03-09-03 07:27
No 415028
This is a good post and it shows how to make carbonyls and aldehydes from halides . I noticed the indication of scheme I , and II where it shows,...........................
R=Cl,Br it should be X=CL, Br otherwise it doesn't make sense
Is it a typo or that is the way it's meant to be..........java
Note: I read the posts and try to understand them, I may be wrong to point out and error or point something out that doesn't make sense and ask for clarification. I'm not a spelling critic and sorry if I make waves, as it's not my intention......
We're all in this world together,
http://www.chiapaslink.ukgateway.net/
(Hive Bee)
03-09-03 07:51
No 415034
for all the non-chemists and C-average chemists, this means that theoretically one could go from safrole to 2-bromosafrole using established methods, then from 2-bromosafrole go to MDP2P using this reaction. Correct?
The working man is a sucker
(Chief Bee)
03-09-03 08:30
No 415044
Yes, either by using the above method, or the one at ../rhodium /halide.
(Moderator)
03-09-03 08:33
No 415045
for all the non-chemists and C-average chemists, this means that theoretically one could go from safrole to 2-bromosafrole using established methods, then from 2-bromosafrole go to MDP2P using this reaction. Correct?
Yes, that's an excellent procedure, but an easier procedure for our purposes accomplishing the same results with equal yields is in Post 292292 (lugh: "Halides to Carbonyls", Chemistry Discourse), and Rhodium's page 
Apparently the authors were unaware of Lieberman's work 
(Hive Bee)
03-09-03 10:21
No 415064
" We wish to report here a new and convenient method for the preparation of aldehydes and ketones from the corresponding halides"...........................
says the article, yes MDP2P is a ketone so I guess the interpretation is correct......java
We're all in this world together,
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