Regioselective 1,4-addition of ammonia to 1-arylalka-1,3-dienes and 1-aryl-4-phenylbuta-1,3-dienes by photoinduced electron transfer
作者:Ryuji Kojima、Toshiaki Yamashita、Kimiko Tanabe、Tsutomu Shiragami、Masahide Yasuda、Kensuke Shima
DOI:10.1039/a605465j
日期:——
The photoamination of 1-arylalka-1,3-dienes 1a–f and
1-aryl-4-phenylbuta-1,3-dienes 1g–k with NH3 in the
presence of p-dicyanobenzene (DCB) gives 4-amino-1-arylalk-2-enes
2a–f and 1-amino-1,4-diarylbut-2-enes 2g–k, respectively. The
photoamination proceeds by nucleophilic addition of NH3 to the
cation radicals of 1+˙ generated by photoinduced
electron transfer to DCB. The regiochemistry of 2 is related to the
distribution of the positive charge in 1+˙ calculated
by the PM3-UHF/RHF method, the stability of the aminated radicals formed by
the addition of NH3 to 1+˙ and the
stability of the aminated anion formed by the reduction of the aminated
radicals by DCB-˙. The stabilities of these
intermediates are estimated by the calculation of the heat of formation by
the PM3-UHF/RHF method. Distributions of the positive charge in
1+˙ and the stabilities of the aminated anion show a
good agreement with the product analysis.
1-芳基烯丙烯-1,3-二烯 1a–f 和 1-芳基-4-苯基丁烯-1,3-二烯 1g–k 在 p-二氰基苯 (DCB) 存在下与氨 (NH3) 的光氨化反应,分别生成 4-氨基-1-芳基烯-2-烯 2a–f 和 1-氨基-1,4-二芳基丁-2-烯 2g–k。光氨化反应通过 NH3 对由光诱导电子转移至 DCB 生成的阳离子自由基 1+˙ 的亲核加成进行。2 的区位化学与通过 PM3-UHF/RHF 方法计算的 1+˙ 中正电荷的分布、NH3 对 1+˙ 加成形成的氨化自由基的稳定性以及由 DCB-˙ 还原氨化自由基生成的氨化阴离子的稳定性有关。这些中间体的稳定性通过 PM3-UHF/RHF 方法计算热焓形成来估算。1+˙ 中正电荷的分布和氨化阴离子的稳定性与产物分析结果良好一致。