Relative reactivity of 2-diphenylphosphinoyl- and 2-diphenyl-thiophosphinoyl-2-[1,3]dithianyllithium as reagents wittig-horner/corey-seebach
作者:Eusebio Juaristi、Barbara Gordillo、Lucia Valle
DOI:10.1016/s0040-4020(01)87612-2
日期:1986.1
The reaction of the title carbanions with several aldehydes and ketones to afford the corresponding ketene dithioketals was studied. It was found that the PO organolithium reagent reacted with both types of carbonyl substrates in good to excellent yields. On the other hand, the PS reagent reacted selectively with aldehydes although in poor yield. This contrasting behavior can not be ascribed to a
研究了标题碳负离子与几种醛和酮的反应,得到相应的烯酮二硫缩酮。发现P = O有机锂试剂与两种类型的羰基底物均以良好至优异的产率反应。另一方面,尽管收率很低,PS试剂选择性地与醛反应。此对比行为不能归因于后者负碳离子的更大的稳定性,因为一个ΔpK一个测量显示,更稳定的有机锂(0.33±O.O8一个的pK一个单位)也更具反应性。P = S类似物的较低反应性可以用氧杂磷杂环丁烷中间体形成中的动力学抑制和/或该五配位磷物质以硫(相对于氧气)作为配体的热力学不稳定性来解释。