M. Valero, E. Giralt, D. Andreu
Jun 10, 1996
Citations
0
Influential Citations
23
Citations
Journal
Tetrahedron Letters
Abstract
Abstract Solid-phase synthesis of cyclic head-to-tail peptides using Boc-based protection schemes and side chain anchoring via the β-carboxyl of Asp can lead to substantial levels of epimerization at the α-carbon of Asp. These problems arise largely from the chemistry used for the incorporation of Boc-Asp(OH)-OFm to the polymer. Several conditions for the attachment of this β-carboxyl to hydroxymethyl or bromomethyl resins have been evaluated, in an attempt to achieve effective, epimerization-free anchorings. The most successful routes involve the use of cesium or zinc salts of Boc-Asp(OH)-OFm.