The preparation of ketones by the carbonation of organolithium compounds
The preparation of ketones by the carbonation of organolithium compounds
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DOI：
10.1021/ja01330a070
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发表时间：
1933-01-01
影响因子：
15
通讯作者：
Van Ess, PR
中科院分区：
文献类型：
--
作者：
Gilman, H;Van Ess, PR
碳酸化是表征活性有机金属化合物的最佳方法之一，因为由该反应形成的酸通常易于分离、纯化和鉴定。然而，据报道苯基锂的碳酸化仅产生痕量的苯甲酸，1并且已经指出，在许多格氏试剂的碳酸化中观察到低产率的酸。实际上，当在最佳条件下进行碳酸化时，来自RMgX化合物的酸的产率是优异的，并且在许多情况下接近基于可用的格氏试剂的理论值。3已证实从苯基锂得到苯甲酸的产率低，我们发现，产率低是由于二苯甲酮的产率不常见（超过70%）。其他有机锂化合物的碳酸化反应表明，该反应可能作为合成某些酮的一种手段是有价值的。幸运的是，有机锂化合物在特定条件下碳酸化可以得到高收率的酸。一个重要的因素是二氧化碳的局部高浓度，这可以通过已经描述的用于格氏试剂碳酸化的程序来实现：即，将有机金属化合物添加到固体二氧化碳4中或将有机金属化合物喷雾到二氧化碳气氛中。23· 0
Carbonation is one of the best methods for the characterization of re-active organometallic compoundsbecause the acid formed by this reaction is, in general, readily isolated, purified and identified. However, the carbonation of phenyl-lithium has been reported to give only traces of benzoic acid, 1 and it has been stated that lowyields of acid are observed in the carbonation of many Grignard reagents. Actually, the yields of acids from RMgX compounds, when carbonation is effected under optimal conditions, 23 are excellent and in many cases approach theoretical values based on available Grignard reagent. 3 A low yield of benzoic acid from phenyl-lithium has been confirmed, and we have found that the poor yield is due to an uncommonly high yield (upward of 70%) of benzophenone. The carbonation of other organolithium compounds indicates that the reaction may be of value as a means of synthesizing some ketones. Fortunately, it is possible; to obtain good yieldsof acids by carbonating organolithium compounds under special conditions. An essential factor is a high local concentration of carbon dioxide, and this can be realized by procedures already described for the carbonation of Grignard reagents: namely, the addition of organometallic compound to solid carbon dioxide4 or spraying the organometallic compound into an atmosphere of carbon dioxide. 23· 0