208927-48-4Relevant articles and documents
3-Bromo-2-fluoropropene - a fluorinated building block. 2-fluoroallylation of glycine and alanine ester imines
Laue, Klaus W.,Haufe, Guenter
, p. 1453 - 1456 (1998)
3-Bromo-2-fluoropropene (4) is prepared in a new three-step synthesis from ammonium α-fluoroacrylate (1) in 31% overall yield. Glycine and alanine ester imines are efficiently alkylated by 4 to give, after deprotection, 2-amino-4-fluoropent-4enoic acid (9) in 63% overall yield, and the α-methylated derivalive 13 in 26% overall yield, respectively. Preliminary results indicate that 4 is potentially a new a-carbonyl cation equivalent.
Enantioselective syntheses of 2-amino-4-fluoropent-4-enoic acids. Isosteres of asparagine
Laue, Klaus W.,Mueck-Lichtenfeld, Christian,Haufe, Guenter
, p. 10413 - 10424 (2007/10/03)
Diastereoselective alkylation of (R)-(+)-camphor-based glycine or alanine esterimines with 3-bromo-2-fluoropropene after hydrolytic deprotection gave (R)-(+)-2-amino-4-fluoropent-4-enoic acid with 38% overall yield and 90% ee, or (R)-(+)-2-amino-4-fluoro-2-methylpent-4-enoic acid (19% overall yield, 59% ee), respectively. Deprotection under drastic conditions was accompanied by hydrolysis of the fluorovinyl moiety to give (R)-(-)-2- amino-4-oxopentanoic acid hydrochloride with 28% overall yield and >95% ee. Ab initio calculations of acetamide and 2-fluoropropene as models for a primary amide or a fluorovinyl group despite of their different electronic structure show a similar electrostatic potential on the van der Waals surface suggesting their isosteric behavior.
