Novel (3 + 2) photocycloadditions with 3-(1-alkynyl)cyclohexenones and tetramethylethylene
作者:Paul Margaretha、H. J. Rathjen、Steven Wolff、William C. Agosta
DOI:10.1039/c39880000841
日期:——
Irradiation of 3-alkynylcyclohexenones (3) with tetramethylethylene gives rise to novel (3 + 2) cycloadducts that can be explained mechanistically in terms of closure of an initial biradical (6) to a vinyl carbene (7), followed by stabilization of the carbene.
Novel [3+2] photocycloadditions of 3-(1-alkynyl)-2-cycloalken-1-ones with alkenes
作者:H. J. Rathjen、Paul Margaretha、Steven Wolff、William C. Agosta
DOI:10.1021/ja00010a035
日期:1991.5
Photochemical cycloaddition of 3-alkynylcycloalkenones with tetramethylethylene at ∼40 o C leads to mixtures of 1:1 adducts that arise largely from 1,5 closure of the biradical intermediate (eq 1), providing examples of a novel [3+2] cycloaddition reaction. Similar reactions occur between these same ketones and 1,1-dimethoxy-2-methylpropene and 1,1-dimethoxyethylene. This and previously observed temperature
3-炔基环烯酮与四甲基乙烯在约 40 o C 的光化学环加成产生 1:1 加合物的混合物,这些加合物主要来自双自由基中间体的 1,5 闭合(方程式 1),提供了新型 [3+2] 环加成反应的例子. 类似的反应发生在这些相同的酮和 1,1-二甲氧基-2-甲基丙烯和 1,1-二甲氧基乙烯之间。这种和之前观察到的温度对三线态双自由基相关重排的影响表明,这种双自由基重排发生在系统间交叉到单线态之前并与之竞争