(Distinctive Doe)
07-04-02 00:09
No 328466
(Rated as: excellent)
styrene + DMSO --very strong base (hydride)--> allylbenzene
The Addition of Dimethyl Sulfoxide Anion to Olefins and the Pyrolysis of Sulfoxides
Cheves Walling and Laszlo Bollyky
JOC 29, 2699 (1964)
Abstract
Base-catalyzed additions of aryl-conjugated olefins, styrene, and 1,1-diphenylethylene to dimethyl sulfoxide occur rapidly at room temperature and give the corresponding methyl 3-arylpropyl sulfoxides in almost quantitative yield. The reaction fails with aliphatic olefins, but occurs with molecules such as allylbenzene which presumably isomerize before addition. The resulting sulfoxides decompose thermally below 200C, giving quantitative yields of 3-arylpropenes with no double bond isomerization. The kinetics of sulfoxide decomposition in diglyme solution have been studied briefly. Decompositions are first order with half-lives (for aliphatic sulfoxides) of 10-30 hr. at 145C, and the reaction should be of general synthetic value.
Experimental
Reagents were commercial materials unless noted, freshly distilled before use. Dimethyl sulfoxide was distilled from CaH2 under reduced pressure and contained not more than 0.001% water by Karl Fischer titration.
Di-n-dodecyl sulfoxide was prepared by treating 1 g. of dodecyl sulfide in 15 ml. of t-butyl alcohol with 0.35 ml. of 30%, H2O2 in 10 ml. of t-butyl alcohol and stirring for 60 hr. at room temperature. The product was recrystallized from ether with m.p. 88.5-89C, yield 97.5%.
The preparations of other sulfoxides are described below.
Addition of Dimethyl Sulfoxide to 1,1-Diphenylethylene.
The dimethyl sulfoxide anion was prepared by dissolving 1 mole of sodium hydride in 400 ml. of dimethyl sulfoxide. One equivalent of 1,l-diphenylethylene was added at 25C; the mixture was quenched with water, extracted with ether, and dried; and the methyl 3,3-diphenylpropyl sulfoxide was recrystallized from 3:1 ether-hexane. The product, m.p. 70-71C.
When the crude sulfoxide from a similar experiment was distilled under reduced pressure at 150-200°C, 3,3-diphenyl-l-propene, characterized as described earlier, (9) was obtained in a 96% over-all yield. Other experiments listed in Table I were carried out similarly, except that, when gas-liquid chromatography (g.l.c.) was used for analysis, the extracted sulfoxide solution was injected directly into the g.l.c. instrument and underwent immediate pyrolysis in the injector block which was maintained at 250C. The identifications of diphenylmethane and 1,1-diphenylcyclopropane were made as in our previous paper.(9)
Addition of Dimethyl Sulfoxide to Styrene.
Addition to styrene was carried out in the same manner under conditions shown in Table II. The intermediate methyl 3-phenylpropyl sulfoxide, m.p. 43-44C, had the expected infrared and n.m.r. spectra.
Pyrolysis of the crude sulfoxide gave allylbenzene, identified by infrared and n.m.r. spectra and g.l.c. retention time, and a small amount of 3,5-diphenyl-l-pentene, identified by infrared spectrum.
Addition of Dimethyl Sulfoxide to Allylbenzene.
Addition to allylbenzene was carried out in the same manner under the conditions indicated. The methyl 3-phenyl-2-methylpropyl sulfoxide, m.p. 80.5-81C, had the expected infrared and n.m.r. spectra.
Pyrolysis gave 3-phenyl-2-methylpropene in 92% yield, idcntified by infrared and n.m.r. spectra and index of refraction, n 23 D ~ 1.5072, lit. 1.5075.
Table II: Addition of DMSO to other Olefins
----------------------------------------
Styrene
Temp: 43C Time:0.5h Base:1.0
Yeild: Allylbenzene 62% (3,5 diphenyl)-1-pentene 28%
Styrene
Temp: 25C Time:0.3h Base:0.22
Yeild: Allylbenzene 71% (3,5 diphenyl)-1-pentene 19%
Styrene
Temp: 25C Time:0.3h Base:2.2
Yeild: Allylbenzene 88% (3,5 diphenyl)-1-pentene 2%
Note: Slow addition of dilute styrene to basic solution.
Allylbenzene
Temp: 25C Time:0.5h Base:1.0
Yeild: 3-phenyl-2-methylpropene 92%
3,3-Diphenylpropene
Temp: 70C Time:2.5h Base:1.0
Yeild: diphenylmethane 50% 3,3-diphenyl-2-methylpropene 30%
----------------------------------------
Base:(Moles/mole of olefin)
(9) C. Walling and L. Bollyky, JOC, 28, 256 (1963).
(Hive Bee)
07-04-02 04:59
No 328541
i have to ask - to any of the wiser bees out there, would an alkali metal alkoxide be at least a theoretical substitute for the hydride.
(PVC-Analog Taste-Tester)
07-04-02 05:30
No 328548
Crafty reaction! This is exactly what I've been looking for! Thanks!!
blondie: alkali metal alkoxide? I don't know, but there are other more powerful bases. If it's of any help, purchasing any type of hydride won't arouse suspicion. The worst that could happen is you'll have to pay a high haz-mat/shipping fee.
Love my country, fear my government.
(Hive Bee)
07-04-02 06:30
No 328573
Hey Foxy2, THANK YOU!! if you ever find yourself in need of the oral sex,
.(Hive Bee)
07-17-02 21:44
No 333733
Post 197071 (dildoque: "allylbenzene", Methods Discourse) I recall this being suggested before. As far as i can see no bees have tried this. Could someone please help me out with formulating a procedure to try this?
What is the mechanism of this reaction?
A nut for a jar of tuna.
-The drive by palindromer
(Distinctive Doe)
07-17-02 21:48
No 333736
As per a request.
Feel free to add input or criticize as needed.
Foxy
One Mole Scale
Step 1
Reagents were commercial materials unless noted, freshly distilled before use. Dimethyl sulfoxide was distilled from CaH2 under reduced pressure and contained not more than 0.001% water by Karl Fischer titration.
Step 2
The dimethyl sulfoxide anion was prepared by dissolving 2.2 mole of sodium hydride in 880 ml. of dimethyl sulfoxide.
Step 3
Dissolve 1 mole(118.178g) Styrene in say 400ml DMSO(or maybee just top off a 500ml pressure equalized addition funnel with DMSO). Drip this into the solution from step 2 over the course of 0.3 hours, while maintaining the temp at 25C. This forms the intermediate methyl 3-phenylpropyl sulfoxide(m.p. 43-44C). Recrystallize from 3:1 ether-hexane?
Step 4
Distillation/pyrolysis of the methyl 3-phenylpropyl sulfoxide. Set up simple distillation and distill the allylbenzene(bp 157C) as its formed. If further purity is desired, fractionally distill.
If all goes well.
Yeild: Allylbenzene 88% (3,5 diphenyl)-1-pentene 2%
Those who give up essential liberties for temporary safety deserve neither liberty nor safety
(Chief Bee)
07-17-02 23:27
No 333786
The only problem I see is that the final pyrolysis/distillation might take 24 h to complete...
(Distinctive Doe)
07-18-02 00:38
No 333816
Perhaps a very hot oil bath/mantel would speed the pyrolysis up, if it goes slow. I would bet you could heat you stillpot well above the boiling point of allylbenzene do to the high boiling point of the sulfoxide, thus immediately driving off any formed allylbemzene.
Those who give up essential liberties for temporary safety deserve neither liberty nor safety
(Philosopher, Stoned)
07-28-02 07:37
No 337971
How would the DMSO addition proceed if MD-styrene or safrole where subed in?
A nut for a jar of tuna.
-The drive by palindromer
(Hive Prodigy)
07-28-02 14:33
No 338047
It would make safrole, so just buy the safrole.
(Hive Addict)
05-15-03 21:11
No 433382
Would calcium carbide be a strong enough base to effect the reaction?
(Chief Bee)
05-15-03 22:13
No 433395
CaC2 won't form the DMSO "dimsyl" anion, as the pKa of acetylenes are around ~29 and that of DMSO exceeds 35.
(Hive Addict)
05-16-03 19:00
No 433570
That's what I (unfortunately) figured. Any suggestions for a more common base (Will CaH2 work?- I don't have its pKa) and thanks for the information.