Modular Hemisyntheses of Boronato- and Trifluoroborato-SubstitutedL-NHBoc Amino Acid and Peptide Derivatives

Modular hemisyntheses of boronato- and trifluoroborato-substituted amino acid and peptide derivatives by using Wittig and C–H iridium-catalyzed borylation as key reactions, are described. Amino ester precursors bearing an aromatic moiety on a lateral chain were prepared by reaction of a new L-NHBoc-amino acid Wittig reagent with the corresponding aromatic aldehydes. After esterification and hydrogenation, the borylation of amino esters was achieved with yields up to 82 % by using the catalysed reaction of bis(pinacolato) diborane reagent (B2Pin2) in the presence of an iridium complex. Interestingly, this iridium-catalyzed borylation was also performed with a dipeptide in 78 % yield. Finally…

Phosphonium-Boronate Amino Acid Derivatives as Fluoride Pincers for 18F-Labelling

The synthesis of phosphonium-boronate amino acid derivatives was achieved by quaternization of o-boronatophenylphosphine with iodo-amino acid derivatives. Preliminary radiolabelling studies demonst...

ChemInform Abstract: P-Chirogenic Secondary Phosphine Oxides: New Stereoselective Synthesis and Applications

P-Chirogenic Secondary Phosphine Oxides: New Stereoselective Synthesis and Applications

ChemInform Abstract: Efficient Stereoselective Synthesis of Boron L-amino Acid Derivatives Using Wittig and Borylation Reactions

The stereoselective synthesis of a new classes of boronato- or trifluoroborato aminoacids and peptides was described using Wittig and C-H iridium borylation as key reactions. A trifluoroborato-thio...

Efficient Stereoselective Synthesis of Boron L-Amino Acid Derivatives Using Wittig and Borylation Reactions

The stereoselective synthesis of a new classes of boronato- or trifluoroborato aminoacids and peptides was described using Wittig and C-H iridium borylation as key reactions. A trifluoroborato-thio...

o-Boronato- and o-Trifluoroborato-Phosphonium Salts Supported by L-α-Amino Acid Side Chain.

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 cou…

P-Chirogenic Phosphines Supported by Calix[4]arene: New Insight into Palladium-Catalyzed Asymmetric Allylic Substitution

The first P-chirogenic mono- and diphosphine ligands supported on the upper rim of a calix[4]arene moiety were synthesized using the ephedrine methodology. The lithiated calix[4]arene mono- and dianions both react with the oxazaphospholidine–borane, prepared from ephedrine, to afford regio- and stereoselectively the corresponding calix[4]arenyl aminophosphine–boranes, by cleavage of the heterocyclic ring at the P–O bond position. Subsequent reactions with HCl and then organolithium reagent and finally decomplexation with DABCO lead to the corresponding calix[4]arenyl mono- or diphosphines. Both enantiomers of the calix[4]arenyl phosphines were obtained either by using (+)- or (−)-ephedrine …

ChemInform Abstract: Modular Hemisyntheses of Boronato- and Trifluoroborato-Substituted L-NHBoc Amino Acid and Peptide Derivatives.

Modular hemisyntheses of boronato- and trifluoroborato-substituted amino acid derivatives are achieved based on the reaction of Wittig reagent (I) with aldehydes followed by Ir-catalyzed boronation.

Multinuclear Cytotoxic Metallodrugs: Physicochemical Characterization and Biological Properties of Novel Heteronuclear Gold-Titanium Complexes

An unprecedented series of titanocene-gold bi- and trimetallic complexes of the general formula [[(η(5)-C(5)H(5))(μ-η(5):κ(1)-C(5)H(4)(CH(2))(n)PPh(2))TiCl(2)](m)AuCl(x)](q+) (n = 0, 2, or 4; m = 1, x = 1, q = 0 or m = 2, x = 0, q = 1) have been prepared and characterized spectroscopically. The luminescence spectroscopy and photophysics of one of the compounds, [[(η(5)-C(5)H(5))(μ-η(5):κ(1)-C(5)H(4)PPh(2))TiCl(2)](2)Au]PF(6), have been investigated in 2MeTHF solution and in the solid state at 77 and 298 K. Evidence for interfragment interactions based on the comparison of electronic band positions and emission lifetimes, namely, triplet energy transfer (ET) from the Au- to the Ti-containing…

ChemInform Abstract: O-Boronato- and o-Trifluoroborato-Phosphonium Salts Supported by L-α-Amino Acid Side Chain.

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 cou…

CCDC 952665: Experimental Crystal Structure Determination

Related Article: Naima Khiri-Meribout, Etienne Bertrand, Jérôme Bayardon, Marie-Joëlle Eymin, Yoann Rousselin, Hélène Cattey, Daniel Fortin, Pierre D. Harvey, and Sylvain Jugé|2013|Organometallics|32|2827|doi:10.1021/om400229p

CCDC 952664: Experimental Crystal Structure Determination

Related Article: Naima Khiri-Meribout, Etienne Bertrand, Jérôme Bayardon, Marie-Joëlle Eymin, Yoann Rousselin, Hélène Cattey, Daniel Fortin, Pierre D. Harvey, and Sylvain Jugé|2013|Organometallics|32|2827|doi:10.1021/om400229p

CCDC 952663: Experimental Crystal Structure Determination

Related Article: Naima Khiri-Meribout, Etienne Bertrand, Jérôme Bayardon, Marie-Joëlle Eymin, Yoann Rousselin, Hélène Cattey, Daniel Fortin, Pierre D. Harvey, and Sylvain Jugé|2013|Organometallics|32|2827|doi:10.1021/om400229p

CCDC 952662: Experimental Crystal Structure Determination

Related Article: Naima Khiri-Meribout, Etienne Bertrand, Jérôme Bayardon, Marie-Joëlle Eymin, Yoann Rousselin, Hélène Cattey, Daniel Fortin, Pierre D. Harvey, and Sylvain Jugé|2013|Organometallics|32|2827|doi:10.1021/om400229p