166540-08-5

Upstream product

• 1099-45-2 ethyl (triphenylphosphoranylidene)acetate 
• 820239-42-7 benzyl N-[(1S)-2-(1H-1,2,3-benzotriazol-1-yl)-1-methyl-2-oxoethyl]carbamate 
• 1142-20-7 N-Cbz-Ala 

Downstream Products

• 1105712-35-3 (4RS)-4-amino-1-ethoxy-2-(triphenylphosphonio)pentane-1,3-dione bromide hydrobromide 
• 1105712-39-7 (5RS)-5-methyl-3-(triphenylphosphoranylidene)pyrrolidine-2,4-dione 
• 183140-46-7 ethyl (4S)-4-(benzyloxycarbonylamino)pent-2-ynoate 
• 1393524-11-2 (3S)-3-(benzyloxycarbonylamino)but-1-yne 

Relevant academic research and scientific papers

Triphenylphosphoranylidene substituted heterocycles as versatile intermediates

N-Cbz-(α-aminoacyl)benzotriazoles 5a-e reacted with (stabilized-methylene)triphenylphosphoranes 6 and 13 to give the corresponding esters 7a-e (66-91%) or nitriles 14a-e (63-85%). Deprotection of N-Cbz-γ-amino-β-oxo-α-triphenylphosphoranylidene esters 7a-

Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 17. Preparation of aliphatic amino acid derived γ-alkoxycarbonyl-amino-β-oxo ylides and pyrolysis to give α,β-acetylenic γ-amino acid and GABA analogues

A series of eleven α-aminoacyl stabilised phosphorus ylides 9-19 have been prepared by condensation of N-alkoxycarbonyl protected amino acids with Ph3P = CHCO2Et using a carbodiimide peptide coupling reagent. Upon flash vacuum pyrolysis at 600 °C, these undergo extrusion of Ph3PO to give the corresponding α,β-acetylenic γ-amino esters 21-29, 33 and 34 in moderate yield. In two cases the terminal alkynes 30 and 31 are also formed. The β-aminoacyl ylide 20 from β-alanine similarly gives the α,β-acetylenic δ-amino ester 35 upon pyrolysis. Regioselective addition of HBr to the triple bond of one acetylenic ester 25 was observed giving a mixture of E and Z α-bromoacrylates 36. Hydrogenation of the N-Cbz acetylenic esters 21-23 and 33 results in N-deprotection and hydrogenation of the triple bond to afford the chiral GABA analogues 37-40 in 70 ->95% ee as determined by 19F NMR of their Mosher amides. Fully assigned 13C NMR spectra of all the ylides and acetylenic ester derivatives are presented.

Convenient synthesis of chiral α,β-acetylenic γ-amino acid derivatives and γ-aminobutyric acid analogues via stabilised ylides

Twelve examples of protected acetylenic amino acids are readily prepared in a two-step procedure involving formation and flash vacuum pyrolysis of chiral aminoacyl phosphorus ylides.