[Donaldson Tan]

wow.. organic chemists.. im impressed although im just a lowly engineer..

[kika_q31]

SOS Please !!!!!
How can I down load this article?


Mander's reagent reference: Tetrahedron Lett. 1983, 24, 5425-5428.

[movies]

You need to have a subscription to the Tetrahedron Letters archives.  If you are at a university, they may have online access.  If not, you could check at a physical sciences library.  This is a very popular journal, so most physical sciences libraries would have it.

Here is a link to the website of the journal:

http://www.sciencedirect.com/science/journal/00404039

[HP]

I am thinking about this route:
Ph-Br + Mg --> Ph-MgBr
Ph-MgBr + Br-CH2CH2CH(OC2H5)2-->PhCH2CH2CH(OC2H5)2 + MgBr2
-->acid hydrolize-->product
I am not sure if 3-brompropanal is commercially available.

[movies]

Yeah, that route ought to work too.  3-Bromopropanal wouldn't be a fun compound to work with because it would rapidly eliminate to form acrolein and acrolein is a pain to deal with too because it polymerizes!

[HP]

Aha movies you right abot 3-brompropanal stability. Also i have some doubts about the Grignard reaction with the ethylacetal of it. What do you think about lability of H from the protected acetal(CH(OR)2)
I have some believe its not enogh labile to react with Grignard like PhMgBr. Heres the known Bodroux-Chichibabin method for reaction Grignard with orthoformiat:
R-MgX + CH(Oc2H5)3--> R-CH(OC2H5)2 + Et-OMgX
By this method it sems reaction stop to the acetal but i dont know. May be Zerevitinov not working here

[movies]

Acetals are usually stable towards Grignard reagents.  There are loads of examples of this.

The orthoformate example is a whole different ballgame.  Orthoesters tend to be a bit more reaction than corresponding acetals.  Note that in your example the product is an acetal, which if it can be isolated from that reaction, must be stable towards the Grignard reagent!

[HP]

Yes indeed movies!
Acetal group good protecting in grignard reaction and in many other too. I am wondering if possible some synthesis of 3-chlorpropanal from epichlorhidrine. Cl-CH2-CH-epovy-CH2 or from the corresponding 3chlor-1,2 propandiol

[movies]

Why not just start with 3-Bromopropanol, protect the alcohol as a silyl ether, then add the Grignard, cleave the silyl ether, and oxidize the primary alcohol?  More steps, but pretty straight forward chemistry.

[HP]

Good idea! Theres so many methods for selective oxidation primary alcohols to aldehydes which do you think best for this preparation?

[movies]

If you do it at the end there isn't really anything else that is particularly sensitive to oxidation, so something like pyridinium dichromate ought to do it.  There are tons of other ways, but chromium is cheap and pretty easy to use.  Other alternatives are TPAP/NMO, Dess-Martin Periodinane, PCC, Swern oxidation (or any of the other activated DMSO oxidations).

[HP]

 Dess-Martin Periodinane method is cool but may be some cheap.Before some time i red an article for very efficient and selective oxidation primary alcohols to cor aldehydes with the system Acetic anhydride/NaNO2. The yelds described are cool also the reagents if it really works But do someone can explain me the mechanism of action and reaction these two reagents and the alcohol The only reaction i can think first is NaNO2+Ac2O-> CH3COONa + CH3CONO2 but may be this compound very unstable and give some reactive intermediates like nitronium or something like?