TY - JOUR
T1 - o-Boronato- and o-Trifluoroborato - Phosphonium Salts Supported by L-α-Amino Acid Side Chain
AU - Bernard, Julie
AU - Malacea-Kabbara, Raluca
AU - Clemente, Gonçalo S.
AU - Burke, Benjamin P.
AU - Eymin, Marie Joëlle
AU - Archibald, Stephen J.
AU - Jugé, Sylvain
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/5/1
Y1 - 2015/5/1
N2 - (Figure Presented) The synthesis of o-boronato- and o-trifluoroborato-phosphonium salts supported by the l-amino acid side chain is described. The synthesis of these new class of amino acid derivatives was achieved by stereoselective quaternization of o-(pinacolato)boronatophenylphosphine with β- or γ-iodo amino acid derivatives which are prepared from l-serine or l-aspartic acid, respectively. The quaternization of the phosphine was performed using either iodo amino ester or carboxylic acid derivatives. In addition, free carboxylic acid and amine derivatives were obtained by saponification or HCl acidolysis of o-boronato-phosphonium amino esters, respectively. The usefulness of these compounds in peptide coupling was demonstrated by coupling an o-boronato-phosphonium amino ester with an aspartic acid moiety. When the o-boronato-phosphonium amino acid or dipeptide derivatives were mixed with fluoride, the corresponding o-trifluoroborated products were cleanly and rapidly obtained in high isolated yields. The hydrolysis of these compounds at room temperature using a phosphate buffer pH 7/CD3CN mixture has shown only traces of free fluoride F- after several days. Finally, a preliminary radiolabeling essay has proven the facile [18F]-fluoride incorporation and high stability of the radiolabeled product in aqueous conditions. Indeed, this new class of boron-phosphonium amino acid derivatives shows promising properties for their applications in synthesis and labeling of peptides.
AB - (Figure Presented) The synthesis of o-boronato- and o-trifluoroborato-phosphonium salts supported by the l-amino acid side chain is described. The synthesis of these new class of amino acid derivatives was achieved by stereoselective quaternization of o-(pinacolato)boronatophenylphosphine with β- or γ-iodo amino acid derivatives which are prepared from l-serine or l-aspartic acid, respectively. The quaternization of the phosphine was performed using either iodo amino ester or carboxylic acid derivatives. In addition, free carboxylic acid and amine derivatives were obtained by saponification or HCl acidolysis of o-boronato-phosphonium amino esters, respectively. The usefulness of these compounds in peptide coupling was demonstrated by coupling an o-boronato-phosphonium amino ester with an aspartic acid moiety. When the o-boronato-phosphonium amino acid or dipeptide derivatives were mixed with fluoride, the corresponding o-trifluoroborated products were cleanly and rapidly obtained in high isolated yields. The hydrolysis of these compounds at room temperature using a phosphate buffer pH 7/CD3CN mixture has shown only traces of free fluoride F- after several days. Finally, a preliminary radiolabeling essay has proven the facile [18F]-fluoride incorporation and high stability of the radiolabeled product in aqueous conditions. Indeed, this new class of boron-phosphonium amino acid derivatives shows promising properties for their applications in synthesis and labeling of peptides.
UR - http://www.scopus.com/inward/record.url?scp=84928901921&partnerID=8YFLogxK
U2 - 10.1021/acs.joc.5b00246
DO - 10.1021/acs.joc.5b00246
M3 - Article
C2 - 25844635
AN - SCOPUS:84928901921
SN - 0022-3263
VL - 80
SP - 4289
EP - 4298
JO - JOURNAL OF ORGANIC CHEMISTRY
JF - JOURNAL OF ORGANIC CHEMISTRY
IS - 9
ER -