Diastereoselective protocols for the synthesis of 2,3-trans- and 2,3-cis-6-methoxy-morpholine-2-carboxylic acid derivatives |
| |
Authors: | Penso Michele Foschi Francesca Pellegrino Sara Testa Andrea Gelmi Maria Luisa |
| |
Institution: | CNR--Institute of Molecular Science and Technology (ISTM), Milano, Italy. michele.penso@istm.cnr.it |
| |
Abstract: | Two diastereoselective and straightforward protocols for the high-yielding synthesis of 2,3-trans- and 2,3-cis-6-methoxy-3-substituted morpholine-2-carboxylic esters were realized in few steps, through the condensation between 5,6-diethoxy-5,6-dimethyl-1,4-dioxan-2-one and an appropriate imine, which is the key reaction to control the C2-C3 relative stereochemistry, followed by a methanolysis/ring-closure tandem reaction sequence. In particular, 2,3-trans-morpholines derive from the R*,S*-product of the acid condensation of N-functionalized alkylimines with the silylketene acetal of the above lactone, whereas 2,3-cis-morpholines derive from the R*,R*-product of basic condensation of an N-tosylimines with the lactone. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|