CAPTURE OF ELECTRON-DEFICIENT SPECIES WITH ARYL HALIDES - NEW SYNTHESES OF HYPERVALENT IODONIUM YLIDES
CAPTURE OF ELECTRON-DEFICIENT SPECIES WITH ARYL HALIDES - NEW SYNTHESES OF HYPERVALENT IODONIUM YLIDES
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DOI：
10.1021/ja00291a044
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发表时间：
1985-01-01
影响因子：
15
通讯作者：
PRAKASH, I
中科院分区：
文献类型：
--
作者：
MORIARTY, RM;BAILEY, BR;PRAKASH, I
结论主要结论如下：（1）Cu ~（2+）促进的酰胺去质子化反应需要含伯基的配体。参考文献2-7中报道的N-保护的氨基酸的羧基仅当保护基是位置（N-甲苯磺酰基-α-氨基酸）中的磺酰基时才可充当初级连接基团。对于这些配体，在Cu 2+存在下，酰胺氢去质子化发生在pH> 5时，强烈预期其pKA值（11-12）为6，7，并形成涉及金属离子配位的五元螯合环羧酸根氧和去质子化的磺酰胺氮供体原子。
ConclusionsThe main conclusions to be drawn from this work are as follows:(1) The Cu2+-promoted amide deprotonation needs ligands containing a primary group. The carboxylic group of the N-protected amino acids, reported in ref 2-7, may act as primary ligating group only if the protecting group is a sulfonyl group in a position (TV-tosyl-a-amino acids). For these ligands the amide hydrogen deprotonation in presence of Cu2+, occurs at pH> 5, strongly anticipating their pKA values (11-12) 6, 7, with formation of a five-membered chelate ring involving in the metal ion co-ordination the carboxylate oxygen and the deprotonated sulfonamide nitrogen donor atoms.