The hetero-Diels–Alder addition of ethyl 2-nitrosoacrylate to electron-rich alkenes as a route to unnatural α-amino acids
作者:John K Gallos、Vassiliki C Sarli、Anastassia C Varvogli、Constantina Z Papadoyanni、Sofia D Papaspyrou、Nicolaos G Argyropoulos
DOI:10.1016/s0040-4039(03)00836-0
日期:2003.5
A new method for the stereoselective synthesis of nonproteinogenic a-amino acids has been developed, which involves hetero-Diels-Alder addition of ethyl 2-nitrosoacrylate to electron-rich alkenes, such as enol ethers, enamines and allylsilanes, and a further two or three step manipulation of the resulting oxazines. (C) 2003 Elsevier Science Ltd. All rights reserved.
A new strategy for the stereoselective synthesis of unnatural α-amino acids
作者:John K. Gallos、Vassiliki C. Sarli、Zoe S. Massen、Anastassia C. Varvogli、Constantina Z. Papadoyanni、Sofia D. Papaspyrou、Nicolaos G. Argyropoulos
DOI:10.1016/j.tet.2004.11.009
日期:2005.1
generated, the stereochemistry of the products being controlled by epimerisation of the thermodynamically less stable isomer to the more stable one, (iii) protection of the N–H group as N-Boc and (iv) finally, N–O bond cleavage of both free and protected products to give proline or bis-homoserine derivatives, respectively. An example with concomitant reduction of the carboxylategroup, resulting in