Neighboring Heteroatom Effect Unique to Aqueous Aldol Reactions of Water-Insoluble Substrates
作者:Bo Li、Chunbao Li
DOI:10.1021/jo500213b
日期:2014.3.7
In the aqueous aldol condensations, Li2CO3 was an efficient catalyst, and therefore base-liable groups such as epoxides, esters, and silyl groups could survive. For heteroaromatic ethanones, the aqueous aldol reactions were accomplished without PTC to give β-hydroxyketones in good yields. The water-mediated condensations of aldosyl hemiacetals with aromatic ketones led to a new carbohydrate-derived
在Li +存在下和在水存在或不存在PTC的情况下,进行酮和醛的反应以生成醛醇产物。已经证明了水性反应相对于有机溶剂介导的反应的几个优点,包括更高的产率,更短的反应时间,更简单的纯化以及更好的官能团耐受性。在水中已经实现了一些在有机溶剂中不发生的反应。成功归因于相邻的杂原子效应。在水性羟醛缩合中,Li 2 CO 3硫醇是一种有效的催化剂,因此可与碱结合的基团(例如环氧化物,酯和甲硅烷基)可以幸免。对于杂芳族乙酮,在没有PTC的情况下完成了水性醛醇缩合反应,以良好的收率得到了β-羟基酮。水介导的醛基半缩醛与芳香族酮的缩合导致定量产率的新的碳水化合物衍生骨架。在某种程度上,这项研究扩大了醛醇缩合和反应的适用性。
Highly chemo- and regioselective rearrangement of α,β-epoxy ketones to 1,3-dicarbonyl compounds in 5 mol dm−3 lithium perchlorate–diethyl ether medium
作者:S. Sankararaman、J. E. Nesakumar
DOI:10.1039/a905619j
日期:——
Epoxides from α,β-unsaturated ketones undergo highly chemo- and regioselective rearrangement to 1,3-dicarbonyl compounds in 5 mol dm–3 lithium perchlorate–diethyl ether medium by a 1,2-migration of the carbonyl group at ambient conditions.
Zur stereochemie der 1,7-dipolaren cyclisierung von konjugierten carbonyl-yliden
作者:Wolfgang Eberbach、Erich Hädicke、Uwe Trostmann
DOI:10.1016/s0040-4039(01)92390-1
日期:1981.1
The 8e-cyclization of the conjugated carbonyl ylide , generated by thermolysis of butadienyloxirane , takes place in the theoretically elected conrotatory fashion yielding the cis-2,3-dihydrooxepin . The stereochemical assignment has been established by X-ray analysis of the Diels-Alder adduct .
The Effects of Solvents and Acid Catalysts on the Rearrangement of 2-Benzylidenecyclohexanone Oxide
作者:Kenichi Hinoue、Masatomo Nojima、Niichiro Tokura
DOI:10.1246/bcsj.44.3096
日期:1971.11
The rearrangement of 2-benzylidenecyclohexanone oxide (I) to 2-phenylcycloheptane-1,3-dione (II) was carried out in the presence of a Lewis acid or a Brφnsted acid in various media-liquid sulfur dioxide, benzene, and ether. The only reaction product of I with a Brφnsted acid in these solvents was the rearranged compound, II. In addition to II, 2-(α-halobenzyl)-2-hydroxycyclohexanone, (III) or (IV)
2-亚苄基环己酮氧化物 (I) 重排为 2-苯基环庚烷-1,3-二酮 (II) 是在路易斯酸或布朗斯台德酸的存在下,在各种介质-液体二氧化硫、苯和乙醚中进行的。I 与布朗斯台德酸在这些溶剂中的唯一反应产物是重排化合物 II。除了 II,2-(α-卤代苄基)-2-羟基环己酮,(III) 或 (IV),也在 I 与路易斯酸在溶液中的反应中得到。观察到溶剂对反应速率和产物分布的显着影响;然而,当使用可以向 I 提供质子的布朗斯台德酸作为催化剂时,没有观察到溶剂效应。从反应过程中反应物、中间体和产物浓度的变化,