Competitive Formation of Ylide and Carbene Intermediates from1?,?*-Excited ?,?-Unsaturated ?,?-Epoxyketones
作者:Norbert Bischofberger、Bruno Frei、Jakob Wirz
DOI:10.1002/hlca.19830660814
日期:1983.12.14
Laser flash photolyses (λ = 265mm) of the γ,λ-epoxyenones 1–3, 7 and 8, the α,β-unsaturated γ,δ-epoxy ester 6, and the epoxytriene 9 at ambient temperature produced short-lived transients with broad absorption maxima in the visible region, which are identified as carbonyl ylides. Comparison of the rather long-wavelength absorption maxima with the results of standard PPP SCF SCI calculations suggests
的γ的激光闪光photolyses(λ=265毫米),λ-epoxyenones 1-3,7和8中,α,β不饱和γ,δ-环氧酯6,和epoxytriene 9在环境温度下产生具有短暂的瞬态在可见光区域的宽吸收最大值,被识别为羰基酰化物。将相当长的波长吸收最大值与标准PPP SCF SCI计算结果进行比较,表明在所有研究的内含物中都存在某种程度的扭曲。这些中间体的寿命约为数百ns,并且Stern - Volmer分析了CH 3衍生自2衍生的羰基叶立德COOH提供了确凿的证据,表明卡宾产物不是通过羰基-叶立德中间体形成的(方案3)。