Improved Schöllkopf construction of quaternary α-amino acids: efficient enantioselective synthesis of integrin LFA-1 antagonist BIRT-377

The Schöllkopf methodology for the asymmetric synthesis of α-amino acids which was previously not applicable to the construction of α,α-dialkylated (quaternary) α-amino acids, has been rendered practical for this purpose and applied in a highly efficient enantioselective synthesis of integrin LFA-1 antagonist BIRT-377. © 2006 Elsevier Ltd. All rights reserved

Novel Applications of the Schöllkopf Chiral Auxiliary: A New and Efficient Enantioselective Synthesis of β-Lactams Possessing a C-4 Quaternary Stereocenter

A new method for the enantioselective synthesis of substituted β-lactams is described based upon an improved alkylation of substituted Schöllkopf chiral auxiliaries by α-haloacetate esters, employing tert-butyllithium as the deprotonating base, and the efficient conversion of the resulting quaternary 2,5-diketopiperazines to the targeted β-lactams

A simple synthesis of the metabotropic receptor ligand (2S)-α-(hydroxymethyl)-glutamic acid and its Fmoc protected derivatives

The highly enantioselective synthesis of (2S)-α-(hydroxymethyl)-glutamic acid 2, a potent metabotropic receptor ligand, was accomplished using the improved Schöllkopf methodology for the construction of quaternary α-amino acids and β-lactams. This was converted to a derivative suitably protected for direct use in Fmoc solid phase peptide synthesis. © 2007 Elsevier Ltd. All rights reserved