作者:Masafumi Ueda、Hideto Miyabe、Masako Teramachi、Okiko Miyata、Takeaki Naito
DOI:10.1021/jo050603z
日期:2005.8.1
The intermolecular radical addition to chiral nitrones 2, 4, 5, and 16 was studied. The isopropyl radical addition to Oppolzer's camphorsultam derivative 2 of glyoxylic nitrone proceeded with excellent diastereoselectivity to give the desired isopropylated product 3a accompanied by the diisopropylated product 3b. A high degree of stereocontrol in the reaction of cyclic nitrone 4 was achieved. The ethyl
分子间自由基加成手性硝酮2,4,5,和16进行了研究。乙氧基硝酮的Oppolzer's樟脑舒坦衍生物2中的异丙基加成以优异的非对映选择性进行,得到所需的异丙基化产物3a以及二异丙基化产物3b。在环状硝酮4的反应中实现了高度的立体控制。用三乙基硼烷将乙基加成到硝基4上,得到所需的乙基化产物9a,并伴有二乙基化产物10a。和乙基化的硝酮11a。为了评价环状硝酮4的效用,在加成反应中使用了几个烷基,这提供了具有优异的非对映选择性的烷基化产物9b - d。在Mg(ClO 4)2存在下,向BIGN 16的乙基加成产生选择性的顺式异构体。相反,即使在不存在路易斯酸的情况下,也将烷基加成至16,以得到抗异构体。