OXIDATIVE COUPLING OF KETONE ENOLATES BY FERRIC-CHLORIDE
OXIDATIVE COUPLING OF KETONE ENOLATES BY FERRIC-CHLORIDE
复制标题
DOI：
10.1021/jo01314a052
复制
发表时间：
1980-01-01
影响因子：
3.6
通讯作者：
HARLOW, RL
中科院分区：
文献类型：
--
作者：
FRAZIER, RH;HARLOW, RL
金属氧化剂已被广泛用于酚类的氧化偶联，但直到最近才出现类似的方法用于氧化二聚酮得到1，4-二酮。令人惊讶的是，虽然铜盐已被用于偶联酮烯醇化物，但据报道，通常用于酚氧化的氯化铁对这种偶联无效。3，6我们发现，尽管以前的观察，氯化铁是一个有效的氧化剂，用于制备1，4-二酮烯醇酮。其烯醇化物已与氯化铁偶联的酮的实例在表I中给出。条目10表明酯也可以通过该方法二聚。在大多数情况下，氯化铁诱导的烯醇化物二聚反应与氯化铜诱导的反应非常相似。然而，虽然二聚与氯化铜是相对敏感的空间congestion周围的碳负离子，3铁系统提供的优势，不是这样的。
Metallic oxidants have been widely employed in oxida-tive couplings of phenols, 1 2 yet only recently have comparable methods appeared for oxidatively dimerizing ketones to give 1, 4-diketones. Surprisingly, while cupric salts have been used to couple ketone enolates, 3™ 5 ferric chloride, commonly used in phenolic oxidations, is reported to be ineffective for such couplings. 3, 6We find that inspite of previous observations, ferric chloride is an effective oxidant for the preparation of 1, 4-diketones from ketone enolates. Examples of ketones whose enolates have been coupled with ferricchloride are given in Table I. Entry 10 demonstrates that esters can also be dimerized by this method. In most respects enolate dimerizations with ferric chloride are quite similar to those induced by cupric chloride. However, while dimerizations with cupric chloride are relatively sensitiveto steric con-gestion around the carbanion, 3 theferric system offers the advantage of not being so.