An efficient intramolecular [4 + 2] cycloaddition reaction of amide-1,6-enynes has been developed, under silver catalysis starting from electron-rich triple bonds. Asymmetric reaction conditions in the presence of Ag salts and chiral atropisomeric MeO-Biphep diphosphine ligands were also investigated and afforded the cyclic amides in good yields and enantiomeric excesses up to 50%.

中文翻译：

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银催化的酰胺-1,6-烯炔的分子内[4 + 2]环加成反应

在银催化下，从富含电子的三键开始的酰胺-1,6-烯炔的有效分子内[4 + 2]环加成反应已得到开发。还研究了在银盐和手性阻转异构的MeO-Biphep二膦配体存在下的不对称反应条件，并以良好的收率得到了环状酰胺，对映体过量高达50％。