Mechanistic diagnosis of aminium salt initiated Diels-Alder cycloadditions in the diene/diene format
Mechanistic diagnosis of aminium salt initiated Diels-Alder cycloadditions in the diene/diene format
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DOI：
10.1021/ja00250a033
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发表时间：
1987-08
影响因子：
15
通讯作者：
D. Reynolds;K. T. Lorenz;Huh-Sun Chiou;D. J. Bellville;R. Pabon;N. L. Bauld
中科院分区：
文献类型：
--
作者：
D. Reynolds;K. T. Lorenz;Huh-Sun Chiou;D. J. Bellville;R. Pabon;N. L. Bauld
对铵盐催化的Diels-Alder反应进行了力学考察。八个二烯/二烯Diels-Alder形式的离散反应体系，包括二聚反应和交叉加成反应，以及一个环丁烷化反应，已经根据多达五个不同的机理标准进行了研究。特别确认了先前提出的阳离子自由基链机理，并排除了除一例外的所有情况下都排除了Bronsted酸催化的机理。如另一个实验室先前提出的，2，4-二甲基-1，3-戊二烯的环二聚反应是通过Bronsted酸催化机理进行的。这些结果支持并进一步拓宽了基于本实验室先前报道的两个环加成体系的详细动力学研究的类似结论。还报道了进行这些反应以及分离和表征环加合物的实验方法。
The aminium salt catalyzed Diels-Alder reaction has been subjected to mechanisticscrutiny. Eight discrete reaction systems in the diene/diene Diels-Alder format, including both dimerizations and cross additions, and also one cyclobutanation reaction, havebeen examined on the basis of as many as five distinct mechanistic criteria. The previously proposed cation radical chain mechanism is specifically confirmed and, among others, a Bronsted acid catalyzed mechanism ruled out in every instance except one. As previously proposed by another laboratory, the cyclodimerization of 2, 4-dimethyl-1, 3-pentadiene is found to proceed via a Bronsted acid catalyzed mechanism. These results support and further broaden similar conclusions based upon detailedkinetic studies on two cycloaddition systems, previously reported by this laboratory. Experimental procedures for performing these reactions and isolating and characterizing the cycloadducts are also reported.