166540-09-6Relevant articles and documents
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
Aitken, R. Alan,Karodia, Nazira,Massil, Tracy,Young, Robert J.
, p. 533 - 541 (2002)
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
Aitken, R. Alan,Karodia, Nazira
, p. 2079 - 2080 (2007/10/03)
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.
