Novel metal-free, readily available chiral catalytic systems for the enantioselective reduction of keto imines are reported. Different β-imino esters were reduced by trichlorosilane in the presence of 10 mol% of a chiral Lewis base easily obtained in one step only from prolinol, in high yields and in up to 85% enantioselectivity; imines bearing an inexpensive and removable chiral auxiliary, were reduced with complete control of the absolute stereochemistry. The methodology was successfully extended to the stereoselective synthesis of α-amino esters.
报道了一种新型无
金属、易获得的手性催化系统,用于酮
亚胺的对映选择性还原。不同的β-亚
氨基酯在三
氯硅烷存在下,通过从脯
氨醇一次性合成得到的10摩尔%的手性路易斯碱进行还原,获得高产率并达到最高85%的对映选择性;具有经济且可去除的手性辅助基团的
亚胺在绝对立体
化学的完全控制下被还原。该方法成功拓展至α-
氨基酯的立体选择性合成。