Juhl Karsten, Jørgensen Karl Anker
Center for Metal Catalyzed Reactions, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
J Am Chem Soc. 2002 Mar 20;124(11):2420-1. doi: 10.1021/ja0175486.
The catalytic enantioselective direct alpha-amination reaction of 2-keto esters with easily available azo dicarboxylates as the nitrogen source and chiral bisoxazoline-copper(II) complexes as the catalyst is presented. The reactions proceed with excellent enantioselectivities and high yields. The scope of the reaction is demonstrated by the direct amination of a series of 2-keto esters having different substituent patterns. The reaction provides an easy catalytic route to optically active syn-beta-amino-alpha-hydroxy esters, as demonstrated for the synthesis of masked syn-beta-amino-alpha-hydroxy esters (as oxazolidinones) and N-Boc-syn-beta-amino-alpha-hydroxy esters. On the basis of the absolute configuration of the products a tentative model for the transition state is suggested.
本文报道了以易于获得的偶氮二羧酸酯为氮源、手性双恶唑啉-铜（II）配合物为催化剂，对2-酮酯进行催化对映选择性直接α-胺化反应。该反应具有优异的对映选择性和高收率。通过对一系列具有不同取代基模式的2-酮酯进行直接胺化反应，展示了该反应的适用范围。该反应为光学活性的顺式-β-氨基-α-羟基酯提供了一条简便的催化合成路线，这在合成掩蔽的顺式-β-氨基-α-羟基酯（如恶唑烷酮）和N-Boc-顺式-β-氨基-α-羟基酯中得到了证明。根据产物的绝对构型，提出了一个过渡态的初步模型。
