Ye Meng-Chun, Zhou Jian, Tang Yong
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, 354 Fenglin Road, Shanghai 200032, China.
J Org Chem. 2006 Apr 28;71(9):3576-82. doi: 10.1021/jo0602874.
The reactions of nitrones with terminal alkynes, catalyzed by chiral (i)Pr-trisoxazoline 2a/Cu(ClO4)2.6H2O under air atmosphere, afforded beta-lactams in moderate to good yields with up to 85% ee. The diastereoselectivity depends on the alkyne. Propiolate gives the trans-isomer as a major product, while the other alkynes afford cis-disubstituted lactams predominantly. Copper(II) salt proved to be an efficient catalyst precursor for the first time in the Kinugasa reaction, and this allowed the reaction to be performed under a practical and convenient condition. An appropriate base used in this reaction was essential to control both diastereoselectivity and enantioselectivity. Compared with primary and tertiary amines, secondary amines gave higher enantioselectivities. The reaction scope and limitation as well as the mechanism were also studied.
在手性异丙基三恶唑啉2a/Cu(ClO4)2·6H2O催化下，硝酮与末端炔烃在空气氛围中反应，以中等至良好的产率得到β-内酰胺，对映体过量率高达85%。非对映选择性取决于炔烃。丙炔酸酯以反式异构体作为主要产物，而其他炔烃主要生成顺式二取代内酰胺。铜(II)盐首次被证明是金井反应中一种有效的催化剂前体，这使得该反应能够在实用且方便的条件下进行。该反应中使用的合适碱对于控制非对映选择性和对映选择性至关重要。与伯胺和叔胺相比，仲胺具有更高的对映选择性。还研究了反应的范围和局限性以及反应机理。
