Asymmetric synthesis of diastereomerically and enantiomerically pure α-amino-γ-nitro carboxylic esters via Michael addition of the titanated bislactim ether of cyclo (-L-Val-Gly-) to nitroolefines
作者:Karla Busch、Ulrich M Groth、Wulf Kühnle、Ulrich Schöllkopf
DOI:10.1016/0040-4020(92)80011-4
日期:1992.7
The titanated bislactim ethers of cyclo(-L-Val-Gly-) 3 and 7 were added highly diastereoselectively in a 1,4-fashion to the nitro olefines 4 yielding the nitro compounds 5. Upon acidic hydrolysis these nitro compounds 5 afforded the α-amino-γ-nitro acid esters 12, which can be hydrogenated to the lactames 14. The oxazoline derivatives 17 were obtained via their nitrile oxides 15 in a subsequent dipolar