Synthesis of α,α-Disubstituted β-Amino Esters and Peptide Derivatives
作者:Eduardo Alonso、Carlos del Pozo、Javier González
DOI:10.1055/s-2002-19326
日期:——
The synthesis of a,a-disubstituted β-amino esters and peptide derivatives from readily available 4-spiro-β-lactams 1 is described. The geminally disubstituted β-amino esters are obtained from the N-Boc spiro β-lactams 2 by treatment with potassium cyanide in methanol. Alternatively, the use of spiro β-lactams 2 as acylating agents of the amino group of C-protected amino acids, allowed its direct incorporation
Staudinger reactions of unsymmetrical cyclic ketenes: a synthetically useful approach to spiro β-lactams and derivatives. Reaction mechanism and theoretical studiesElectronic supplementary information (ESI) available: Spectral data for compounds 4b–4m and 5b–5d and Cartesian coordinates and energies (hartrees) of zwitterionic intermediates (IZ1, IZ2, IZ3, and IZ4) and transition structures (TS1, TS2, TS3 and TS4). See http://www.rsc.org/suppdata/p1/b1/b103279h/
作者:Eduardo Alonso、Carlos del Pozo、Javier González
DOI:10.1039/b103279h
日期:2002.2.6
efficient and operationally simple synthesis of tetrahydrofuran-derived spiro-β-lactamsusing the ketene–imine cycloaddition route is described. Also the preparation of spiro-N-sulfonyl-β-lactam derivatives, which are analogs of monobactams, is reported. As far as we know, this is the first time that an unsymmetrical cyclic ketene is used in a Staudinger-type reaction. The experimental evidence suggests