pHarmacist
(Hive Bee)
12-23-02 17:37
No 392220
      Allylation of Aromatic Compounds
(Rated as: good read)
    

This invention relates to a process for the allylation of aromatic compounds and particularly to a process for treating aromatic compounds with an allylic halide in the presence of a copper halide catalyst to form the desired product.

The process of this invention has an advantage over the well-known Frieder-Crafts reaction in the presence of aluminum chloride; for example, the product of the reaction of benzene and allyl chloride in the presence of cupric chloride as a catalyst comprises allylbenzene, whereas the reaction in the presence of aluminum chloride yields .beta.-chloropropylbenzene and diphenylpropane as the products thereof [Nenitzescu and Isacescu, Ber. 66, 1100 (1933)].


EXAMPLE I

In this example 92 g. (1.0 mol) of toluene and 19 g. (0.25 mol) of allyl chloride along with 35 g. (0.26 mol) of cupric chloride were placed in a round bottom flask provided with heating and refluxing means. The flask was heated to a temperature of 90 DEG C. and maintained in a range of from 90 DEG to 110 DEG C. for a period of 12 hours at atmospheric air pressure. At the end of this time, heating was discontinued and the flask allowed to return to room temperature. The reaction mixture which comprised a dark-amber liquid was separated from the brownish-green powder catalyst. The liquid was treated by conventional means, analysis of the final product showing the presence of a mixture of ortho- and meta-allyltoluenes.

EXAMPLE II

A mixture comprising 120 g. (1.5 mol) of benzene, 40 g. (0.52 mol) of allyl chloride and 36 g. (0.27 mol) of cupric chloride was placed in the glass liner of a rotating autoclave. The autoclave was sealed and nitrogen pressed until an initial operating pressure of 30 atmospheres was reached. Following this, the autoclave was heated to a temperature of 150 DEG C. and maintained thereat for a period of 4 hours, the maximum pressure at this time rising to 70 atmospheres. At the end of the 4 hour period, heating was discontinued and the autoclave allowed to return to room temperature, the final pressure at room temperature being 35 atmospheres. This excess pressure was discharged, the autoclave was opened and the reaction product comprising a dark-amber liquid and brownish-green powder was recovered. The liquid was separated from the catalyst powder by filtration and subjected to conventional means of purification, analysis of the final product disclosing the presence of allylbenzene.

EXAMPLE III

In this example a mixture comprising 134 g. (1.0 mol) of t-butylbenzene, 75 g. (1.0 mol) of allyl chloride and 10 g. (0.15 mol) of cupric chloride was placed in the glass liner of a rotating autoclave. The autoclave was sealed and nitrogen pressed in until an initial operating pressure of 30 atmospheres was reached. The autoclave was then heated to a temperature of 157 DEG C. and maintained at a range of from 157 DEG to 161 DEG C. for a period of 4 hours, the maximum pressure at this temperature reaching 65 atmospheres. At the end of the aforementioned time period, heating was discontinued and the autoclave was allowed to return to room temperature. After cooling, the excess pressure was discharged and the reaction product comprising a dark red-brown turbid liquid and a dark tan catalyst was recovered. The liquid was separated from the catalyst powder by filtration and subjected to conventional means of purification. Analysis of the product disclosed the presence of a mixture of ortho, meta-,and para-allyl-t-butylbenzenes, the para isomer being present in an amount of about 70 percent of the mixture.

EXAMPLE IV

In this example, a mixture comprising 94 g. (1.0 mol) of phenol, 30 g. (0.25 mol) of allyl bromide and 36 g. (0.27 mol) of cupric chloride is placed in the glass liner of a rotating autoclave. The autoclave is sealed and nitrogen pressed in until an initial pressure of 30 atmospheres is reached. Thereafter, the autoclave is heated to a temperature of 150 DEG C. and maintained thereat for a period of 4 hours. At the end of this time, heating is discontinued and the autoclave is allowed to return to room temperature and the excess pressure is discharged. After recovery of the reaction mixture, separation from the catalyst and purification, analysis of the final product will disclose the presence of a mixture of ortho-, meta-, and paraallylphenols.

Reference: Patent US3678122

"Turn on, Tune in and Drop Out"
 
 
 
 
    pHarmacist
(Hive Bee)
12-23-02 18:02
No 392231
      Allylation via Diazotization     

It would be nice if someone could provide us with the fulltext procedure for Ar allylation via diazotization.

Example:
http://www.orgk1.lu.se/page/posterhemsidan.pdf


"Turn on, Tune in and Drop Out"
 
 
 
 
    Aurelius
(Hive Addict)
12-23-02 18:23
No 392239
      extra step
(Rated as: good read)
    

US 2654791  synthesis of 2-halo-1-phenylpropane
(then any number of routes to allylbenzene.

Example 1:

To a cool mixture of about 360cc of anhydrous benzene and about 260cc of nitropropane is added about 77g of anhydrous aluminum chloride slwoly and with continuous stirring.  a solution of 77g of allyl chloride in an equal volume of dry benzene is added slowly to the mixture, and the temperatureo of the reaction mixture is maintained between -5C and 0C.  On completing the addition of the allyl chloride solutino the stirring is continued for about 1/2 hour, and the mixture is hydroyzed in a cold aolution of 50cc concentrated hydrochloric acid in 500cc water.  The benzene layer is sep'd and the water extracted three more times with benzene.  The pooled extracts are combined and dried over a sodium carbonate and sodium sulfate mix.  2-chloro-1-phenylpropane is obtained from the mixture by distillation at 70-74C at 3mm pressure in a good yield.

Notes on the Reaction:

Other small aliphatic nitroalkanes may be used.  Nitromethane (cheap, OTC), may be used. 

Allyl alcohol may be used in the same molar proportions as the chloride to give slightly smaller yields by the same reaction.

Although the reaction should be carried out with cooling as stated in the procedure when using the allyl chloride, the allyl alcohol variation can and should be run at a slight reflux for best yields.

References Cited by the Patent:

US patent 2076201

Nenitzescu et al.: "Ber. der deut. Chem. Gesell.," vol. 66, pages 1100-1103 (1933).

Thomas: "Anhydrous Aluminum Chloride in Organic Chemistry," pages 783-4 (1941).


 
 
 
 
    pHarmacist
(Hive Bee)
12-23-02 18:38
No 392250
      Aurelius, of course, but     

The patent that I refered to above has the advantage over the one that you refer to by simply forming allylbenzene instead of beta-chloropropylbenzene as described in the patent that you talk about. It's a shame that no yields are given. Especially considering that isomers are formed, in cases where substitued benzenes are used as starting materials of course, no isomer-ratio is given mad.


"Turn on, Tune in and Drop Out"
 
 
 
 
    Aurelius
(Hive Addict)
12-24-02 09:08
No 392456
      Antoncho's old posts     

Post 300151 (Antoncho: "Allylation of arenes w/ allyl alcohol and ZnCl2", Novel Discourse)
 
 
 
 
    Rhodium
(Chief Bee)
12-25-02 15:43
No 392827
      Aniline to Allylbenzene by Diazotization (Diazall)
(Rated as: excellent)
    

Aromatic Allylation via Diazotization: Metal-Free C-C Bond Formation
F. Ek, O. Axelsson, L-G. Wistrand, T. Frejd
J. Org. Chem. 67(18), 6376-6381 (2002) (../rhodium/pdf /allylation.diazotization.pdf)



Abstract

A new method for the synthesis of allyl aromatic compounds not involving any metal-containing reagent or catalyst has been developed. Arylamines substituted with a large number of different substituents were converted via diazotizative deamination with tert-butyl nitrite in allyl bromide and acetonitrile to the corresponding allyl aromatic compounds. The allylation reaction was found to be suitable for larger scale synthesis due to short reaction times, a nonextractive workup, and robustness toward moisture, air, and type of solvent.

DOI:10.1021/jo0258103

Synthesis of Allyl-3,5-dinitrobenzene

Neat 3,5-dinitroaniline (75 g, 0.41 mol) was added in portions to a solution of tert-butyl nitrite (84.6 mL, 0.71 mol) and allyl bromide (530 mL, 6.15 mol) in CH3CN (25 mL), keeping the temperature between 11-15C. Before the addition of the final 25% of 3,5-dinitroaniline, more tert-butyl nitrite (21 mL, 0.18 mol) was added. The reaction mixture was then stirred at room temperature (23-25C) for 1 h. Excess tert-butyl nitrite, allyl bromide, and CH3CN were distilled off from the reaction mixture at reduced pressure, and toluene (500 mL) was added to the orange-brown residue.

The resulting mixture was filtered twice through alumina pads (1010 cm), and the pads were washed with a total of 1.5 L of toluene. The toluene was distilled off at reduced pressure, and isooctane (200 mL) was added to the remaining pale yellow residue. The mixture was stirred at 60C for 0.5 h (to extract the partly polymerized allyl bromide and 1,2,3-tribromopropane from the product) and then cooled to approximately -50C. As soon as a white precipitate (partly polymerized allyl bromide and 1,2,3-tribromopropane) started to form, the solvent was decanted (including the precipitate) and to the remaining yellow oil another portion of isooctane (200 mL, 20C) was added. The oily residue in isooctane was then stirred at -50C with a spatula until crystals formed. In some cases, it was necessary to decant the isooctane phase and add fresh isooctane before the oil started to crystallize. The crystals (remaining in the flask) were then washed twice with isooctane (precooled to -50C) at -50C. Residual isooctane was removed at reduced pressure to give 78.9 g of Allyl-3,5-dinitrobenzene as a yellow oil containing less than 4% of 3,5-dinitrobromobenzene according to 1H NMR analysis. This corresponds to 89% yield of allyl-3,5-dinitrobenzene. In an alternative procedure, the crystals (after washing with isooctane at -50C) were collected by filtration at -50C and then washed once with isooctane (precooled to -50C). The latter method gave the same yield of slightly purer Allyl-3,5-dinitrobenzene.


I believe that this workup is definite overkill, unless dealing with a very expensive substrate, or if the substrate forms a large amount of by-products. I'd suggest that after the removal of the reaction solvents and excess allylbromide (recover, purify and re-use), the crude product is diluted with an equal amount of diethyl ether (or possibly pet. ether), then washed twice with 5% HCl, twice with 10% aqueous NaHCO3 and once with saturated aqueous NaCl, then dried over anhydrous MgSO4, filtered and the filter cake washed with a little ether. The solvent is then distilled off (recover, purify and re-use), and the residue is then fractionately distilled (under vacuum, if necessary) to isolate the pure allylbenzene.
 
 
 
 
    Antoncho
(Official Hive Translator)
12-26-02 08:25
No 392996
      Some notes plus safrole synthesis.
(Rated as: good read)
    

It's a pity that this diazotization allylation works poorly only on electron-deficient rings... And requires at least an eightfold amt of allyl bromide.

OTOH, it should bee a good route from p-fluoroaniline...

Now, as for allylations. Do you remember this: Post 292833 (Antoncho: "Allylations.", Novel Discourse)? I always thought i was an immensely exciting direction - should someone find a way to make this rxn applicable to phenolic ethers.

And - as an addition to that post... This was brought to us by Apis52, who is no longer with usfrownfrownfrown (and his last words were "Don't ever make anything for salefrown"). Let us all wish him good luck!

Here it is:




Synthesis of safrole.

7,15g allyl chloride, 34,3g methylenedioxybenzene and 0,15g Cu powder (made from CuSO4/Zn) are heated for 10,5hrs in a flask equipped w/a thermometer and an efficient RC (good enough to condense the vapours of allyl-Cl) at gentle reflux.

Heating is stopped when the temperature has risen from 47 C to 125 C. The rxn is mixed w/ether, filtered and washed 2x25mls brine, 3x25mls 5% aq NaOH, 3x25 brine, dried w/MgSO4 and distilled thru a 20cm Vigreux column.

Double ditillation gives 44-46% yield of fraction containing 85% safrole, which is further purified thru its mercuric derivative (does anone know WTF is that?)






So, as you can see, this isn't overly exciting beecause of the low yield and the need of triple molar xcess of benzodioxole. Still, given the scarcity of methods applicable to making safrole, this is, IMHO, a good piece of information.

I wish that someday, someone, explores this ground and finds THE way to allylation of benzodioxole.

I'd guess this should bee something mild, copper salt-catalysed. And, maybee, allyl alcohol instead of allyl halides..... Well, this is all useless rambling at this stage anyway, so i'll just shut upsmile




Antoncho
 
 
 
 
    Lego
(Hive Bee)
08-07-03 14:59
No 452348
      Direct allylation of aromatic compounds
(Rated as: excellent)
    

Chemistry Letters, 1997, 137-138 (http://www.angelfire.com/scifi2/lego/journals/25.djvu)



Molybdenum- and Tungsten-catalyzed allylation of aromatic compound with allylic esters and alcohols



A novel method to substitued aromatic compounds with allylic groups using oxygen-containing allylic compounds in the presence of molybdenum or tungsten carbonyls under neutral conditions has been developed. The method is applicable to one step synthesis of methyl eugenol.

[...]

Table 1. Transition metal-catalyzed reaction of cinnamyl compounds (Ph-CH=CH-CH2-OR) with p-xylenea

Allylic compound (M) cat. Time (h) Yield (%) b
1a (R2=Ac) Mo(CO)6 72 80
1b (R2=CHO) Mo(CO)6 24 80
1c (R2=CO2CH3) Mo(CO)6 6 76
1d (R2=H) Mo(CO)6 6 42
1c (R2=CO2CH3) (p-xylene)Mo(CO)3 6 76
1c (R2=CO2CH3) (bipy)Mo(CO)4 72 0
1c (R2=CO2CH3) W(CO)6 24 78
1c (R2=CO2CH3) Cr(CO)6 72 0
1c (R2=CO2CH3) Pd2(dba)3CHCl3+4PPh3 24 0c
1c (R2=CO2CH3) Ru3(CO)12 24 0c

a p-Xylene (10 ml), allylic compound (0.47-0.86 mmol) and Mo(CO)6 (10 mol%) at 139 C under Ar.
b Determined by GC
c Phenylpropene and 3-phenylpropene were obtained as major products.

[...]

The present allylation method can be applied to the synthesis of aromatic ethers having allylic substituents, some which serve as useful perfumes.
Thus methyl eugenol can be readily synthesized in one step as shown in Eq. 2 in 56% yield accompanied by its minor isomer formed in 9%.

[...]

The candle that burns twice as bright burns half as long
 
 
 
 
    demorol
(Hive Bee)
08-27-03 07:47
No 455991
      Iridium-Catalyzed Allylation     

Rhodium- and Iridium-Catalyzed of Electron-Rich Arenes with Allyl Tosylate

Abstract: The allylation of electron-rich arenes with allyl tosylate proceeded at 0C in the presence of [Rh(nbd)(CH3CN)2]PF6. Various oxigenated arenes were allylated with high para-selectivity in almost all cases. Especially in the reaction of anisoles, the tendency was remarkable.

Typical procedure: To a suspension of an arene (5 mmol) and [Rh(nbd)(CH3CN)2]PF6 (0.025 mmol) in dry toluene (1 mL), allyl tosylate (0.5 mmol) was added at 0C under nitrogen atmosphere. After stirring for 15 h or 24 h, the mixture was filtered through a plug of silica, followed by washing with ether (~ 30 mL). The solvent was removed under reduced presure to give an oil that was further purified by flash column chromatography to yield an allylated product. The products obtained were identiified by comparison of their 1H NMR spectral data with those of commercial or reported samples.





Reference: Synlett, 10 (2003), pp 1431-1434

I'm dreaming of the white crystals.
 
 
 
 
    Rhodium
(Chief Bee)
03-19-04 04:51
No 496121
      Rh/Ir-catalyzed Allylation     

Rhodium- and Iridium-Catalyzed Allylation of Electron-Rich Arenes with Allyl Tosylate
Naofumi Tsukada, Yasushige Yagura, Tetsuo Sato, Yoshio Inoue
Synlett 1431-1434 (2003) (../rhodium/pdf /safrole.allyltosylate.rh-ir.pdf)
DOI:10.1055/s-2003-40859

Abstract
The allylation of electron-rich arenes with allyl tosylate proceeded at 0C in the presence of [Rh(nbd)(CH3CN)2]PF6. Various oxygenated arenes were allylated with high para-selectivity in almost all cases. Especially in the reaction of anisoles, the tendency was remarkable.

The Hive - Clandestine Chemists Without Borders
 
 
 
 
    Flippie
(Hive Bee)
03-20-04 01:03
No 496279
      safrole mercuric derivative     

Double ditillation gives 44-46% yield of fraction containing 85% safrole, which is further purified thru its mercuric derivative (does anone know WTF is that?)

Purification of safrole from essential oils with mercuric acetate yields high purity safrole without distillation.

For more info ../rhodium/chemistry /mercury.html

Flippie

For Research Use Only