Fragmentation of Alkoxy Radicals and Oxidative Elimination of Alicyclic Iodides
摘要:
The azaallyl cation-mediated [4 + 3] cycloaddition with spiro[2.4]hepta-4,6-diene by the procedure of Schmid provides the tricyclic cycloadducts of general type 3. The keto bridge of the cycloadducts 17c, 21, and 22 has been cleaved by PhI(OAc)(2)-I-2 (Suarez cleavage), which involves P-fragmentation of an alkoxy radical, to furnish iodo lactones 19, 32, and 30a,b, respectively. Subsequent oxidation of these alkyl iodides has been investigated to develop a new synthetic route for bridgehead olefins (i.e., 33) of medium-sized carbocycles.
Fragmentation of Alkoxy Radicals and Oxidative Elimination of Alicyclic Iodides
摘要:
The azaallyl cation-mediated [4 + 3] cycloaddition with spiro[2.4]hepta-4,6-diene by the procedure of Schmid provides the tricyclic cycloadducts of general type 3. The keto bridge of the cycloadducts 17c, 21, and 22 has been cleaved by PhI(OAc)(2)-I-2 (Suarez cleavage), which involves P-fragmentation of an alkoxy radical, to furnish iodo lactones 19, 32, and 30a,b, respectively. Subsequent oxidation of these alkyl iodides has been investigated to develop a new synthetic route for bridgehead olefins (i.e., 33) of medium-sized carbocycles.
A renewable amine for photochemical reduction of CO2
作者:Robert D. Richardson、Edward J. Holland、Barry K. Carpenter
DOI:10.1038/nchem.1000
日期:2011.4
Photochemical reduction of CO2 (to produce formic acid) can be seen both as a method to produce a transportable hydrogen-based fuel and also to reduce levels of CO2 in the atmosphere. However, an often overlooked necessity for photochemical CO2 reduction is the need for a sacrificial electron donor, usually a tertiary amine. Here, we describe a new strategy for coupling the photochemical reduction
CO 2 的光化学还原(产生甲酸)既可以看作是一种生产可运输的氢基燃料的方法,也可以看作是降低大气中 CO 2水平的一种方法。然而,光化学 CO 2还原的一个经常被忽视的必要性是需要牺牲电子供体,通常是叔胺。在这里,我们描述了一种将 CO 2的光化学还原与光化学水分解相结合的新策略,并通过一个原型示例来说明这一点。我们的替代策略不是寻求完全消除使用外部还原剂,而是使还原剂可回收。与直接耦合 CO 2相比,这具有两个潜在优势还原和水氧化。首先,它允许使用现有化学进行两个氧化还原反应,其次,它允许这些反应在互不相容的条件下进行。
[4 + 3] Cycloadditions of cyclic oxyallyls and cyclic 1,3-dienes.
作者:Shu-juan Jin、Jong-Ryoo Choi、Jonghoon Oh、Dongha Lee、Jin Kun Cha
DOI:10.1021/ja00149a014
日期:1995.11
The [4 + 3] cycloaddition of the oxyallyl intermediates, derived from 2-chlorocyclohexanone and related compounds, to cyclic 1,3-dienes under the Fohlisch conditions (Et(3)N in CF3CH2OH) has been examined to assess its scope and limitations. Effects of substitution with alkyl or alkoxy groups on the cyclohexanone ring, along with variations of the base, solvent, or ring size have been investigated. Also included is a comparison between the Fohlisch cycloaddition and the Schmid cycloaddition (utilizing alpha'-chloroenamines). These reactions of cyclic oxyallyls afford tricyclic or tetracyclic cycloadducts of considerable molecular complexity with a well-defined stereochemical outcome and, thus, represent a new synthetic route to functionalized medium-sized carbocycles and heterocycles.
Fragmentation of Alkoxy Radicals and Oxidative Elimination of Alicyclic Iodides
作者:Jinhwa Lee、Jonghoon Oh、Shu-juan Jin、Jong-Ryoo Choi、Jerry L. Atwood、Jin Kun Cha
DOI:10.1021/jo00102a019
日期:1994.11
The azaallyl cation-mediated [4 + 3] cycloaddition with spiro[2.4]hepta-4,6-diene by the procedure of Schmid provides the tricyclic cycloadducts of general type 3. The keto bridge of the cycloadducts 17c, 21, and 22 has been cleaved by PhI(OAc)(2)-I-2 (Suarez cleavage), which involves P-fragmentation of an alkoxy radical, to furnish iodo lactones 19, 32, and 30a,b, respectively. Subsequent oxidation of these alkyl iodides has been investigated to develop a new synthetic route for bridgehead olefins (i.e., 33) of medium-sized carbocycles.