Pin Frédéric, Comesse Sébastien, Garrigues Bernard, Marchalín Stefan, Daïch Adam
URCOM, EA 3221, UFR des Sciences & Techniques, Université du Havre, 25 rue Philippe Lebon, BP:540, F-76058 Le Havre Cedex, France.
J Org Chem. 2007 Feb 16;72(4):1181-91. doi: 10.1021/jo062077x. Epub 2007 Jan 23.
Bismuth(III) triflate was found to promote the formation of stable cyclic N-acyliminium species in remarkable catalytic amounts (1 mol %). The alpha-amidoalkylation process seems to be effective in intermolecular and intramolecular manners leading to alpha-substituted lactams and heterocyclic systems containing azacycles, respectively. By comparing our results with those obtained with the classical Lewis acids as catalysts, it was evidenced clearly that the use of bismuth(III) triflate had been efficient for nearly all alpha-acetoxy lactams we used, except for N-acyliminium precursors bearing a sulfur atom. Also, the process seems to be easy, general, and clean, having diastereoselectivity comparable to protocols using classical Lewis acids and resulting in the formation of polyheterocyclic systems in good to excellent yields (64-99% in acetonitrile as solvent).
发现三氟甲磺酸铋（III）能以显著的催化量（1摩尔%）促进稳定的环状N-酰基亚胺离子物种的形成。α-氨基烷基化过程似乎在分子间和分子内方式中都有效，分别导致α-取代的内酰胺和含有氮杂环的杂环体系。通过将我们的结果与使用经典路易斯酸作为催化剂获得的结果进行比较，清楚地证明，除了带有硫原子的N-酰基亚胺离子前体之外，对于我们使用的几乎所有α-乙酰氧基内酰胺，使用三氟甲磺酸铋（III）都是有效的。此外，该过程似乎简单、通用且清洁，具有与使用经典路易斯酸的方案相当的非对映选择性，并能以良好至优异的产率（在乙腈作为溶剂时为64-99%）形成多杂环体系。
