A variety of chiral N-phosphinyl α-imino esters have been synthesized for the first time from ketoesters and phosphinylamide, which were then reduced by L-selectride to give the corresponding N-phosphinyl-protected α-amino esters. The reduction proceeded very well with excellent chemical yields (88–98%) as well as high diastereoselectivities (96:4 to 99:1). Some of these products could be obtained without column chromatography and recrystallization. The chiral phosphinyl auxiliary could be easily cleaved under acidic conditions.
首次合成了一系列手性的N-磷酰基α-亚胺酯,这些酯是通过酮酯和磷酰胺合成的,然后通过L-selectride还原得到相应的N-磷酰基保护的α-氨基酯。还原反应的化学产率很高(88-98%),对映选择性也很高(96:4到99:1)。其中一些产物可以在不经过柱层析和再结晶的情况下获得。手性磷酰辅助基可以在酸性条件下轻松解除。