Exceptional reactivity and selectivity of lower-order cyanocuprates in the SN2′-substitution of propargyl acetates
Exceptional reactivity and selectivity of lower-order cyanocuprates in the SN2′-substitution of propargyl acetates
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DOI：
10.1016/j.ica.2005.06.045
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发表时间：
2006-04-10
影响因子：
2.8
通讯作者：
Krause, N
中科院分区：
文献类型：
--
作者：
Jansen, A;Krause, N
本文研究了几种炔丙基乙酸酯与低级氰基铜酸盐RCu（CN）Li的S（N）2 ′-取代反应。在吡啶基取代的底物的情况下，获得了良好至优异的化学产率的所需的吡啶基丙二烯，而没有螯合物的形成，这往往阻碍相应的反应的铜酸镁。在类似的手性仲炔丙基乙酸酯的S（N）2 '-取代反应中，低级氰基铜酸酯得到了比铜酸镁或氰基-Gilman试剂具有更高的对映选择性的所需联烯。因此，它们的高反应性和低外消旋化联烯的倾向使得低级氰基铜酸盐成为这些S（N）2 '-取代反应的选择试剂。(c)2005 Elsevier B. V.保留所有权利。
The S(N)2'-substitution reaction of various propargyl acetates with lower-order cyanocuprates RCu(CN)Li was examined. In the case of pyridyl-substituted substrates, good to excellent chemical yields of the desired pyridylallenes were obtained without chelate formation, which often hampers the corresponding reactions of magnesium cuprates. In the analogous S(N)2'-substitutions of chiral secondary propargyl acetates, lower-order cyanocuprates gave the desired allenes with higher enantioselectivities than magnesium cuprates or cyano-Gilman reagents. Thus, their high reactivity and low tendency to racemize allenes make lower-order cyanocuprates the reagents of choice for these S(N)2'-substitution reactions. (c) 2005 Elsevier B.V. All rights reserved.