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  		    CHEM GUY:  P2P production references
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the second method is of particular interest, not only because it's neat,
but also because it looks like it is attempted less.


All references were first discovered in "The Journal of Forensic
Science", Vol. 37, yr 1992, pp. 301-322


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From "Tetrathedron Letters", No 45, pp 3323-3326, yr 1964


"...


(R1-CH-OR)-P(+)-(C6H5)3  --{base}-->  (R1-C(+)-OR)-P(+)-(C6H5)3


--{R2-C=O-R3}-->  R1C(OR)=C(R2)R3  --{H3O(+)}-->  R1(C=O)CH(R2)R3


The phosphonium salt (I, R=R1=CH3) was prepared by dissolving triphenyl
 phosphine (76.4 g., 0.29 mol) and [alpha]-methyl ether [5] (28.4 g.,
0.30 mol) in 125 mL of benzene.  After standing for 40 hrs. the mixture
was filtered and washed with ether giving a white solid (112 g., 88%
yield) consisting of the crude phosphonium salt containing one molar
equivalient of benzene crystallization.  ...  This salt is slightly
hygroscopic on exposure in air but can be stored indefinitely in a
sealed container.


The ylid (II R=R1=CH3) resulting from treatment of (I, R=R1=CH3) with
base was found to be very unstable at room tempature, the
characteristic red color dissappearing within a few seconds.
Accordingly, the preparation and reaction of this ylid was best carried
out at -40 C. The general procedure used for the preparation of the
crude enol ethers (III, R=R1=CH3) was as follows:  The phosphonium salt
(33 mmol) was suspended in 40 mL of glyme at -40 C under nitrogen.
Potassium t-butoxide (33 mmol) in 15 mL of glyme was added with
stirring over 5 minutes.  At this point a solution of the aldehyde or
ketone (30 mmol) in 5 mL of glyme was added over five minutes.  The
mixture was allowed to warm to rrom tempature over one hour and was
then directly distilled.


The distillates obtained were usually quite pure samples of enol ethers
in the reaction of aldehydes.  ...


...


The methyl ketones were conveniently prepared from the enol ethers by
mixing with one equivalent of water with 0.5% HCl and enough methanol
to effect solution.  The solution was heated to boiling and the solvent
was then evaporated to give relatively pure samples of the ketones in
practically quantitive yields.  ...


TABLE I


Methyl Ketones from Aldehydes and Ketones


Carbonyl Compound / Methyl Ketone / Yield [6] /...


Benzaldehyde / 3-Phenyl-2-propanone / 88% /..."


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From "The Journal of Organic Chemistry", Vol 54, yr 1989, page 733-4


"...


Scheme II


R2-CH=C(R1)-NO2  --{2 H(+)/ CF3SO3H}-->  ... --{C6H6}-->


C6H5-CH(R2)-(C=O)-R1


...


TABLE I
Nitro olefin/ R1/ R2/ temp C/ time/ [alpha]-phenylmethyl ketone/ Yield


4a/ CH3/ H/ -40/ 1 min/ 6a/ 85%
...


In a typical procedure, a solution of 2 nitropropene (4a) (300 mg) in
benzene (total amount of benzene used was 30 equivalents) was added to
a well-stirred solution of TFSA (10 equiv with respect to 4a) and
benzene with the co-solvent of methylene chloride cooled to -40 C in a
dry ice-acetone bath.  The reaction mixture was immediately (after 1
minute) poured into large excess dry methanol (100 mL) cooled to -78 C
with vigorous stirring [8].  After being warmed to the ambient
tempature (10-15 min), the yellow solution was diluted with water
(150 mL), nuetralized with powdered NaHCO3, and saturated with NaCl.
The solution was extracted with CH2Cl2, dried over Na2SO4, and
concentrated, and the residuewas flash chromatographed (SiO2) to give
pure 3-phenylpropan-2-one (6a) from nitro olefin (4) is demonstrated in
Table I.


..."


==========================


Also there is:  "Journal of the American Chemical Society", Vol 93,
yr 1971, pp 524-526


It uses acetate salts of Mg or Ce to add acetone to an olefin but it
does not refer to benzene specificly, whereas the Forensic Science
article that referenced it implied that you could just use Mg(OAc)2 and
benzene to create P2P.


"As a representive example, the reacton of acetone with octene-1 in the
 presence of manganic acetate under a nitrogen atmosphere was studied
in detail. A solution of ocetene-1 (7.5 mmol), acetone (200 mmol), and
 manganic acetate (15 mmol) in glacial acetic acid (40 mL) containing
10% potassium acetate was heated at 85 until the brown manganic color
 had dissappeared.  Three major products were isolated after the work
-up:  the saturated ketone ... (I, 1.13 mmol); an unsaturated ketone
.... (II, 0.54 mmol)... ; and a keto acetate ... (III, 1.78 mmol)..."