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
将环(-L-Val-Gly-)3和7的钛酸二内酯醚以1,4-方式高度非对映选择性地加入到硝基烯烃4中,得到硝基化合物5。在酸性水解时,这些硝基化合物5提供了α-氨基-γ-硝基酸酯12,其可以被氢化成内酰胺14。在随后的偶极(2 + 3)-环加成中,通过它们的腈氧化物15获得恶唑啉衍生物17。这些衍生物17可以被水解为含有恶唑啉的氨基酸酯18。