Photochemical [3 + 2] cycloaddition of α,β-acetylenic ketones with simple olefins
作者:Saadat Hussain、William C. Agosta
DOI:10.1016/s0040-4020(01)92377-4
日期:——
3-pentyn-2-one (1) in the presence of tetramethylethylene, isobutylene, and cis- and trans -2-butene leads to vinyldihydrofurans 3,5,6, 8 and 9 (Table 1) in a novel [3 + 2] photochemical cycloaddition reaction. A related adduct 13 is formed between tetramethylethylene and 5,5-dimethyl-3-hexyn-2-one (2). A mechanism incorporating an initial biradical that closes to a carbene (eqn 3) is proposed to account for
3-戊炔-2-酮(照射1在四甲基,异丁烯和的存在下)的顺式-和反式-2-丁烯导致vinyldihydrofurans 3,5,6,8和9(表1)中的新的[3- + 2]光化学环加成反应。在四甲基乙烯和5,5-二甲基-3-己炔-2-酮(2)之间形成相关的加合物13。提出了一种机制,该机制包含了一个接近卡宾(等式3)的初始双自由基,以解释这些反应。