The Vespiary

The Hive => Novel Discourse => Topic started by: Rhodium on August 10, 2002, 02:10:00 AM

Title: Hydrocinnamic acid to P2P - byzantine or real?
Post by: Rhodium on August 10, 2002, 02:10:00 AM

3-Phenylpropionic acid (Hydrocinnamic acid) can be made in many ways (or bought for about $100/kg), and by subjecting it to Hell-Vollhardt-Zelinski reaction conditions (PBr₃/Br₂) you'll afford 2-Bromo-3-Phenylpropionic acid, which in turn can be reduced to 2-bromo-3-Phenyl-1-propanol (allylbenzene bromohydrin) using for example NaBH₄ together with I₂ or H₂SO₄.

By refluxing this bromohydrin lightly in dilute NaOH it will cyclize through an intramolecular Williamson etherification to form 2-benzyloxirane (allylbenzene epoxide), which finally is refluxed with LiI in EtOAc for a few hours to effect the isomerization of the epoxide to its methyl ketone; Phenyl-2-Propanone.

(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000343683-file_m4aq.gif)

Title: yield
Post by: GC_MS on August 10, 2002, 08:31:00 AM

Any thoughts on the yield of P2P when using hydrocinnamic acid?

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Doped(TM) since 19.... euhm... a long time  :)

Title: Energetically unfavorable.
Post by: neuromodulator on August 15, 2002, 02:40:00 AM

R-CO2H's dislike being reduced, although I've never tried DIBAL.
All in all, I would predict a somewhat low yield overall. 
Even with good yields in each step, there would still be a few too many steps there (5) to be of much utility.

 . . .

Rapture Tastes So Sweet.