作者:Alena Hölzl、Thorsten Bach
DOI:10.1016/j.jphotochem.2015.09.020
日期:2016.12
Upon irradiation at λ = 254 nm in acetonitrile solution, the title compounds formed 8-(2-formyloxyethyl)-substituted 2,4-diazabicyclo[4.2.0]oct-1(8)-en-3,5-diones, which underwent thermal cyclobutene ring opening to 6-substituted pyrimidine-2,4-diones. The reaction cascade results in an unprecedented formal 1,5-shift of the substituent at the pyrimidine-2,4-dione core. It was shown that the reaction
在 乙腈溶液中于λ = 254 nm处辐射后,标题化合物形成8-(2-甲酰氧基乙基)-取代的2,4-二氮杂双环[4.2.0] oct-1(8)-en-3,5-二酮,其进行热环丁烯开环,以生成6-取代的嘧啶-2,4-二酮。反应级联导致嘧啶-2,4-二酮核心上的取代基发生前所未有的形式上的1,5-移位。结果表明,反应可能通过乳清酸盐的[2 + 2]光环加成产物进行,在λ照射下,其收率较高(分别为85%和98%) = 300 nm。在更短的波长下,内酯羰基碳原子和α-碳原子之间的键断裂被诱导,如氘标记实验所示,这通过分子内氢抽象而导致上述环丁烯。