Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, ROC.
J Org Chem. 2013 Aug 16;78(16):7970-6. doi: 10.1021/jo401161h. Epub 2013 Aug 7.
A distinct chemoselectivity in the gold-catalyzed oxidative cyclization of 3,5-dien-1-ynes was observed when 3,5-dichloropyridine N-oxide replaced 8-methylquinoline N-oxide as the oxidant; the resulting cyclopentadienyl aldehydes were obtained in good yields. The altered chemoselectivity is attributed to a prior enyne cyclization in the presence of 3,5-dichloropyridine N-oxides. The use of N-iminopyridium ylide enables a similar iminocyclization reaction to give cyclopentadienyl imines efficiently. Our experimental data support a prior gold-catalyzed cyclization of 3,5-dien-1-ynes to form gold carbene, followed by the oxidation with N-oxide.
当 3,5-二氯吡啶 N-氧化物取代 8-甲基喹啉 N-氧化物作为氧化剂时，观察到金催化的 3,5-二烯-1-炔的氧化环化具有明显的化学选择性；以良好的收率得到环戊二烯基醛。改变的化学选择性归因于在 3,5-二氯吡啶 N-氧化物存在下的烯炔环化。使用 N-亚氨基吡啶𬭩叶立德可以有效地进行类似的亚胺环化反应，得到环戊二烯基亚胺。我们的实验数据支持 3,5-二烯-1-炔的金催化环化形成金卡宾，然后用 N-氧化物氧化的反应历程。
