Use of the<i>N</i>-Formyliminium Ion Cyclization for the Synthesis of 3-Aryl-1,2,3,4-tetrahydroisoquinolines
作者:Bruce E. Maryanoff、Mary C. Rebarchak
DOI:10.1055/s-1992-26350
日期:——
Classical cyclization procedures for the synthesis of 3-arylisoquinolines are fraught with complications. Here, we present the application of an N-acyliminium cyclization to such target molecules. N-(1,2-diarylethyl)formamides 1, 4a-4d, and 4f were cyclized to the respective tetrahydroisoquinolines by using paraformaldehyde under mildly acidic conditions. Yields ranged from good to excellent. Cyclization of 4e was unsuccessful possibly because the presence of the 4-methoxyphenyl group leads to ionization of the formamido group.
传统的3-芳基异喹啉合成中的环化过程充满了复杂性。在此,我们介绍了一种N-酰亚胺基环化反应在合成这些目标分子的应用。N-(1,2-二芳基乙基)甲酰胺1, 4a-4d和4f,在温和酸性条件下使用多聚甲醛,成功环化形成相应的四氢异喹啉。产率从良好到优秀。4e的环化未能成功,可能是由于4-甲氧基苯基的存在导致了甲酰氨基的离子化。