Catalytic N -Cbz Deprotection of Amino Acids and Dipeptides over Spherical SiliaCat Pd(0)
- 1Zeochem Silica Materials, 2500 Boulevard du Parc Technologique, Québec, QC, Canada, G1P 4S6
- 2Istituto per lo Studio dei Materiali Nanostrutturati, CNR, via U. La Malfa 153, Palermo, Italy, 90146
Abstract
Investigation of hydrogenolytic removal of N -benzyloxycarbonyl ( N -Cbz) protecting groups from amino acid and dipeptide derivatives mediated by spherical SiliaCat Pd(0) under mild conditions using an H 2 -filled balloon allowed to optimize reaction parameters including solvent composition, substrate concentration, Pd loading, temperature, and catalyst particle size. The spherical catalyst enabled efficient N -Cbz deprotection at Pd loadings as low as 0.25–0.50 mol% under selected conditions, with high conversions, isolated yields, and selectivities across a broad range of amino acid derivatives. The methodology was successfully extended to N -Cbz-protected dipeptides, although substrate-specific optimization of solvent composition and Pd loading was required for more challenging substrates. Catalyst particle size primarily influenced reaction kinetics, with smaller particles providing faster deprotection, and larger particles advantageous for packed-bed continuous-flow applications. The catalyst showed useful chemoselectivity in the presence of Boc and tert -butyl ester protecting groups, while selective N -Cbz removal in the presence of benzyl esters could be achieved through appropriate control of reaction conditions. Comparison with commercial heterogeneous Pd catalysts showed that the spherical organosilica catalyst provided a favorable combination of complete conversion, high isolated yields, and consistently low Pd leaching. Overall, these results establish spherical SiliaCat Pd(0) as a practical, non-pyrophoric, and versatile heterogeneous catalyst for N -Cbz deprotection of amino acid and dipeptide derivatives, supporting its application in peptide-oriented synthesis.
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BibTeX
@misc{pandarus2026catalytic,
title = {{Catalytic N -Cbz Deprotection of Amino Acids and Dipeptides over Spherical SiliaCat Pd(0)}},
author = {Valerica Pandarus and Samuel Cashman-Kadri and Rosaria Ciriminna and François Béland and Mario Pagliaro},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010886/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010886/v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Catalytic N -Cbz Deprotection of Amino Acids and Dipeptides over Spherical SiliaCat Pd(0)
AU - Valerica Pandarus
AU - Samuel Cashman-Kadri
AU - Rosaria Ciriminna
AU - François Béland
AU - Mario Pagliaro
PY - 2026
DA - 2026/10/22
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010886/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010886/v1
AB - Investigation of hydrogenolytic removal of N -benzyloxycarbonyl ( N -Cbz) protecting groups from amino acid and dipeptide derivatives mediated by spherical SiliaCat Pd(0) under mild conditions using an H 2 -filled balloon allowed to optimize reaction parameters including solvent composition, substrate concentration, Pd loading, temperature, and catalyst particle size. The spherical catalyst enabled efficient N -Cbz deprotection at Pd loadings as low as 0.25–0.50 mol% under selected conditions, with high conversions, isolated yields, and selectivities across a broad range of amino acid derivatives. The methodology was successfully extended to N -Cbz-protected dipeptides, although substrate-specific optimization of solvent composition and Pd loading was required for more challenging substrates. Catalyst particle size primarily influenced reaction kinetics, with smaller particles providing faster deprotection, and larger particles advantageous for packed-bed continuous-flow applications. The catalyst showed useful chemoselectivity in the presence of Boc and tert -butyl ester protecting groups, while selective N -Cbz removal in the presence of benzyl esters could be achieved through appropriate control of reaction conditions. Comparison with commercial heterogeneous Pd catalysts showed that the spherical organosilica catalyst provided a favorable combination of complete conversion, high isolated yields, and consistently low Pd leaching. Overall, these results establish spherical SiliaCat Pd(0) as a practical, non-pyrophoric, and versatile heterogeneous catalyst for N -Cbz deprotection of amino acid and dipeptide derivatives, supporting its application in peptide-oriented synthesis.
ER -