tiresias3 (Stranger)
08-17-02 19:15
No 346251
      A Cheeper Wittig.  Bookmark   

The Queen Is Dead.--The Smiths
(Diana, that is; Strike is now a member of the U.S. penal system.)
And no, Charles is NOT allowed to marry Camilla, but they can still fuck if they want IMNSHO, but that would *technically* be a sin, would it not?
Tantric Yoga is not for everybody, who is EVERYBODY really?
The word _Catholic_ is defined as 'universal' by the dictionary.
Penultimately, the Pope is not supposed to be a Pole, but rather an Italian of course.
Ultimately, each household (man, woman, nice house) should have only one child per generation, but that comes later where we are.
That particular rule is all ready The LAW in China, however, but who could swallow whom? 
On the other hand, no one is allowed to pick whether they have a boy, a girl or a hermaphrodite, and the doctors are not allow to change anyone's God given gender, but some men will always want to dress up in their mother's clothes I'm afraid, but as long as they are either in a gay friendly bar, it's All Hallow's Eve (Oct. 31, BTW) or at home I don't see any harm in it, although it does freak me out a bit (in a good way).
(I personally am not a member of that particular set btw.)
However, I AM a lifetime member at BACKSTREET.


At any rate,

The Emmons-Horner Modification goes something like the following:

In this experiment we vill use a modification of the Wittig reaction, discovered in-de-PEN-dent-ly by Emmons and Horner, in which the less expensive tri-Et phosphite is substituted for tri-Ph phosphine. 

Use BzCl as the halide component, and create an initial phohphonium salt which undergoes an Arbuzov reaction (Nu- attack of the Cl- ion on one of the ethoxy groups to form EtCl and a phosphonate).

Abstraction of an H+ with NaOMe forms the ylide, which is treated with trans(not cis!!!)-1,4-di-Ph-1,3-butadiene.

The use of commercial NaOMe allows all these steps to be completed easily in one lab session.  It is essential that all reagents and apparati be dry, since water destroys ylides.  When not weighing out the NaOMe, cap the bottle.

Synthetic Outline:

(EtO)3P: + Ph-CH2-Cl + NaOMe --> (EtO)2(O-)P+CH-Ph, which is The Wittig-Horner Ylide.

TWHY + (Z)-cinnamonaldehyde --> 1,4-di-Ph-1,3-butadiene.

Experimental Pro-Seed-Ure:

Measure 3.0 mL BzCl (Achtung!, lachrymatorious, a real tear jerker) in the hood and pour into a dry 10 mL gradumatated glass cylinder.  Use blue nitrile kid gloves while handling all this stuff!

Transfer to a 50 mL RBF and add 4.2 mL tri-Et phosphite and a boiling chip (Mr Chips!).  Attach the water cooled reflux condenser and, using a heating mantle or a peanut oil bath, gently add Dell (i.e., heet) and reflux the solution gentlemanly for 3600 seconds (or s for short). 

Elimination of EtCl starts at 130 C and the rxn. temp. rises as the reaction pro-seeds.

After the Time is UP, bring IT back here again by removing the source of the Dell. 

It's as (Simple) v as (E/Z) as Pie, where pi = 3.14159265...!!!!

Nextly, while the other solution is cooling, mass out 1.5 g fresh NaOMe into a dry 125 mL Erl-N-Meyer flask (re-member that Florence has phat hips!). 

Stopper that flask to keep this reagent dry.

When the yellow phosphonate liquid has cooled to 72 F, pour that solution into the glass RBF from Step One, Above (see above), and add 25 mL dimethylformamide (DMF).

Put a lid or a stopper on the flask and swirl it vigorously in an ICE bath at O C.  Quickly, add 3.0 mL of (Z)-cinnamonaldehyde by pipette to the O so Cool reaction solution.  The mixture rapidly turns flaming red and the pro-duct soon begins to crystallize from the red, cold solution.

Swirl (I love the Swirlies!!!) the flask for yet another 300 s in the ICE bath, and then let it stand at room temperature (which is, of course, a variable with occasional swirling) for between (far and far between!!!) AnOTHER 1200 to 1800 s.

Add 10mL H2O and 10mL MeOH to the flask, swirl to loosen the crystals, and filter the solid with a Buchner Fucker Funnel.  Wash the pro-duct with rain water (it needs to be clean, though) unti the rojo is no mo in the crystals.

Now you may wash the cyrstals with several 1 mL aliquots of MeOH, until the washings are colorless this time, not the crystals!

The resultant diene is a pale yellow HC with an mp of 150 to 151 degrees C.  Allow this HC to air dry under a gentle 40W lamp bulb with the electricity plugged in and the switch turned on before massing it.

Do NOT calculate the percent yield.  They left the math to me, remember?


1.  Outline a multistep synthetic total synthesis of
(E)-stilbene (Ph-CH=CH-Ph) using only au natural almond oil from BI-LO, Winn-Dixie, Kroger, SAM'S, Wal-Mart, SuperWalMart, SuperSuperWalMart, PigglyWiggly, Bell's, EarthFare, FoodLion etc...

Also, you should check out The Velvet Underground if you haven't all ready.


"While Frank Sinatra sings stormy weather, the flies and spiders get along together.  Cobwebs drip from an old sinking ceiling."--CAKE, _Fashion Nugget_

Post Script

Henry never liked that CD, one Adam gave it a chance and I ate it, too!!

Yours Truly, No Friend of Cromwell.


(Chief Bee)
09-02-02 18:18
No 351833
      Do you have any references?  Bookmark   

Do you have any references?
(Old P2P Cook)
09-02-02 20:14
No 351869
      Stilbene.  Bookmark   

1.  Outline a multistep synthetic total synthesis of
(E)-stilbene (Ph-CH=CH-Ph) using only au natural almond oil

How about a one step procedure: couple the benzaldehyde using TiCl2 in THF. This is even a named reaction but the name escapes me at the moment. I don't know, though, if this produces the trans isomer.

For bonus points procede to use the stilbene in the preparation of phenanthrene. Give an analogous procedure for the preparation of picene.
(Master Whacker)
09-03-02 02:19
No 352011
      References; comments  Bookmark   


A reference for that Wittig-Horner is a follows: Ber. 92, 2499(1959).  Sodium methoxide is not a very good base as yields are only in the low 60% range.  The best base system to use is a massive (3X) molar excess K-tBuO.  This reaction is commonly used in college level organic labs as a fail-safe demonstration of the Horner modification of the Wittig reaction.
(Old P2P Cook)
09-05-02 04:05
No 352793
      Low valent titanium coupling reaction.  Bookmark   

McMurry Reaction