Photolyse de melanges de pentyne-3one-2 et de tetramethylethylene dans C 6 H 6 conduisant aux cis- et trans-ethylidene-4 methylene-5 tetramethyl-2,2,3,3tetrahydrofuranne se transposant envinyldihydrofuranne et en oxetanne。Mecanisme: mise en jeu de carbenes
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