2,3-Dihydro-2,2,2-triphenylphenanthro[9,10-d]-1,3,2-λ5-oxazaphospholes react with carbon dioxide in an overall second order reaction at room temperature to give 3H-phenanthro[9,10-d]oxazol-2-ones and triphenylphosphine oxide in good yields.
AbstractThe reactions of 2,3-dihydro-2,2,2-triphenylphenanthro[9,10-d]-1,3,2-λ5-oxazaphospholes with aromatic aldehydes lead to the corresponding 2-substituted phenanthro[9,10-d][1,3]oxazoles via an aza-Wittig reaction in good yields. Graphical abstract
摘要2,3-二氢-2,2,2- triphenylphenanthro [9,10-的反应d ] -1,3,2-λ 5个-oxazaphospholes与芳香醛导致相应的2-取代的菲并[9,10- d ] [1,3]恶唑可通过aza-Wittig反应获得高收率。 图形概要
Unexpected radical mechanism in a [4+1] cycloaddition reaction
作者:István Bors、Mihály Purgel、Péter Pál Fehér、Tamás Varga、Gábor Speier、László Korecz、József Kaizer
DOI:10.1039/d1nj00660f
日期:——
9,10-Phenanthrenequinone monoimines (2,7-R-PQI, R = tBu, H, Br, NO2, 1a–d) undergo a [4+1] cycloaddition reaction with triphenylphosphine to give 2,3-dihydro-2,2,2-triphenylphenanthro[9,10-d]-1,3,2λ5-oxazaphospholes (3a–d). During the reaction, highly colored radicals are formed as intermediates, which were characterized by EPR and UV-vis spectroscopy. The formation rate and the rate of decay of these