The wacker seems to be everyones favorite route to MDP2P, but this is just to remind us all that there are other ways out there.  And they're extremely OTC.  The notes for a oxone based oxidation of isosafrole were recently found and I will relay them to you here.  Note the most pertinent deviations from standard procedure (via rhodium) are the lowered solvent volumes, lack of base (buffer), and the smaller amount of oxone.

20g (12.2mmol) alkene in 200mL MeOH
56.4g (18.3mmol) oxone in 250mL H2O

The oxone used was dry, not a solution.  After adding the oxone to water, the solution remained murky after five minutes and it was decided to simply combine with the alkene soln. as is.  After combining the solutions, a reflux condenser was started with cold water.  The reaction did not evolve any noticeable heat in the first hour and was left to run overnight.  After returning, the solution was a single phase of bright orange.  The flask was flooding with water, the organic layer was separated and the aqueous layer washed 3x with DCM.  The extracts were combined and the solvent removed.

The remaining crude material was refluxed in 150mL 15% H2SO4 for four hours then extracted once again 3x with DCM.  The DCM was washed once with aq NaOH, once with H2O, and once with a brine solution.  The brine solution resulted in a small emulsion which did not resolve itself upon 24hr of standing.  The emulsion was thus combined with the organic layer and the the entire solution frozen.  The organic solution was decanted from the ice, the solvent removed, and the MDP2P distilled under vacuum to yield ~12.1g (60.5% w/w yield).

Note:
1.  There is no need to buffer the solution as the epoxide will simply open under acidic conditions to either the glycol or the methyl ether, both of which are hydrolyzed in the next step.
2.  It is suspected though not confirmed that solvent volumes can be further reduced.  Specifically the amount of methanol necessary to solvate the alkene and allow the reaction to proceed in a single phase.

i have no experience with oxone but from what i remember reading those are yields to be proud of.  i seem to recall oxone yields suck compared to peracid.  the highest yielding oxidation of this nature is chromic's buffered peracetic coupled with hcl pinacol rearrangement as jon stated.  chromic's buffered peracetic is easily found on rhodium, but here's chromic's original post on the use of hcl instead of h2so4 for the rearrangement followed by a few happy bees putting in their 2 cents.  the thread can be found on your hive archives at hiveboard/chemistrydiscourse/000476034.html

Chromic
(Synaptic Self-Mutilator)
12-12-03 08:38
No 476334
                  HCl is so good it's GOLDEN!
(Rated as: excellent)          

V_V, you're right on the money. Thank you! *hugs*

This ketone of a friend's is good, infact, great! It turned to slush in about 1-2 minutes in the freshly made bisulfite solution (normally this can take 5-60 minutes)

May I make a suggestion to any other bee to try using a 15% HCl rearrangement? Write-up is as follows (attentive bees will notice this is actually 5M HCl):

From the extracts from a peracid rxn containing .3mol isosaffy (48.6g), the glycol is added to: 75mL MeOH, 125ml H2O then 125ml 31.25% HCl. The mixture is refluxed 2.5 hours, the oil drained from the bottom of a sep funnel and further extracted 3x60ml DCM. The ketone distilled and at least an 80% yield can be had...

I'm expecting this yield to be closer to 85% if this guy had a better lab. This really is phenomenal if it's as good as it appears to me. I always heard of 60% yields with the peracetic/performic (likely because of the losses in the acid-catalyzed rearrangement), and I knew it's possible to hit 70% with a proper vacuum distillation... so I wouldn't be surprised if one can hit 85% of theory using this HCl rearrangement. It's almost as great as Ritter's work on the tosic method, and certainly a lot more OTC.

amine had this to say:

amine
(Hive Bee)
04-14-04 08:56
No 500742
                  Chromic is god!!!          

Wow, as we speak, swim has the most beautiful ketone distilling a light green color comming over at around 147C.  Swim used chromics technique and wow, it is sooooo much easier than the H2SO4 hydrolysis, the reaction looks clean throughout and you can see product formation, the syruppy glycol slowly turns into globules of a dark golden color. The rest of the solution remains orange.
Post reaction a beautiful dark golden oil falls to the bottom.

Wow....this by far is the cleanest method swim has used.
Props to chromic.

had swims vacuum adapter break but swim ghetto rigged something that works (using a 2 neck 500ml flask...) and a stopper with a hole in it.

abolt verified the procedure:

abolt
(Hive Addict)
06-19-04 04:52
No 514235
                  Isosafrole hydrolysis          

In a 3L flatbottom flask, fitted with a condensor and magnetic stirring, was added 600 ml dichloromethane and 56 g sodium bicarbonate followed by 180 g (1.11 mol) isosafrole. A solution of performic acid, prepared from 120 ml 50% hydrogen peroxide and 230 ml 85% formic acid, was added dropwise over the course of 3 hours, and the mixture was allowed to stir for an additional 22 hours. The organic layer was separated and washed with 3x 200 ml distilled water. After evaporation of the solvent there was left 255 g of a dark red oil, which was stored in the refridgerator for 12 hours, after which it took on the viscosity of motor oil.

The dark red glycol was dissolved in 250 ml methanol in a 3L flatbottom flask fitted with condensor and magnetic stirring, 400 ml distilled water were added and the mixture was heated to reflux with stirring. 430 ml 30% HCl was added and refluxing was continued for 3 hours and the contents were allowed to cool to room temperature. The bottom dark oily layer was separated off (honey-mint smell) and the aqueous layer was extracted twice with 200 ml DCM. The oil and extracts were pooled and washed twice with 200 ml distilled water, once with 300 ml 10% NaHCO3, and once with 300 ml brine. The bicarbonate washing took on a brown color, the other washings were clear. The solvent was stripped off and the residue was distilled with aspirator vacuum: first came a small forerun (15 ml) of isosafrole, followed by 133 gr rose/golden 3,4-methylenedioxyphenylacetone, an overall yield of 67%.

MDP2P was tested positive with bisulfite.

The remainder left in the distilling flask was 25-28ml tar, which had some transparency to it. Aside from the extra yield, this hydrolysis also seems much cleaner, in appearance and work up.smile

Previous yields using H2SO4 hydrolysis were around 50%.

Well done Chromic.

Is this the paper that jon was referring to?

Looking around at various threads it appears keeping the temperature down is the key to higher yields.

Eleusis had a write up adapted from a japanese paper where they precooled the performic and the isosafrole before adding them together.

I was wondering if the reason HCl gives better yields on the 2nd step is because it would react cooler than the sulfuric?

Also found this in the paper below and am wondering if adding water as in the post above is a bad idea?

Generally, as the concentration of the acids decreased, a decreasing trend in the formation of 1
and a steady increase of both 2 and 3 was observed.

This may be attributed to the involvement of the increasingly larger quantity of water present, which
can act as a base to remove the adjacent protons from both intermediates C and A to afford 2 and 3,

Salat

Makes sense, I'm finding thinking of chemistry in terms of energy change makes some things more understandable. 

DCM with HCL sounds much better than water and MeOH.  The paper seems to indicate 4M as the best amount of HCl to use.

Salat

Unfortunately I can't compare my H2SO4 to HCl results because the operator made a freshman mistake.  After flooding the post-oxidation reaction mixture water, the operator failed to close his sep funnel stop cock and consequently lost the entire second DCM extraction.  Alas, he trudged along and reduced the glycol.  The final yield of MDP2P was 30% w/w.

cut a rag into many small pieces and mop it all up, chuck the pieces of rag back in the sep funnel and shake DCM through them a few times..

those dcm extractions are all product man

i have many many really nice post 2000 refs on wacker oxidation id like to share them and you guys might like to see, i was going to save them for another thread, as they are more the oxidation of safrole rather than the epoxidation of isosafrole.. maybe we can adjust the title

Even though the scientific literature seems to discuss epoxidation alot more

Alot of methods new methods are using H2O2 as the oxidant as Psychexplorer pointed out a while ago but i pretty much ignored. The by products of H202 oxidation seems to be just water.. i still have some research to do here. I think a few of us are in the same boat.

As you can see, these are more focused on molecular oxygen and the sole oxidant, in Cu free conditions.

there are really some nice little finds in here i think, so enjoy!