Synthesis and reactivity of furoquinolines bearing an external methylene-bond: access to reduced and spirocyclic structures
作者:Xavier Bantreil、Carine Vaxelaire、Thomas Godet、Evelyne Parker、Carole Sauer、Philippe Belmont
DOI:10.1039/c1ob05354j
日期:——
A family of furoquinolines were efficiently obtained through a tandem acetalization/cycloisomerization process catalyzed by (5 mol%) silver imidazolate polymer and triphenylphosphine, and diversity was brought by the use of 7 different alcohol groups. From these furoquinolines, 3 examples of reduced derivatives could be obtained (d.r. up to 94 : 6), 10 different spiroketal derivatives by hetero-Diels–Alder reaction (d.r. up to 20 : 1), 8 hetero-[5,5]-spirocycles by cycloaddition with dibromoformaldoxime (d.r. up to 86 : 14) and finally 6 hetero-[5,6]-spirocycles by [4 + 2] cycloaddition with ethyl 3-bromo-2-(hydroxyimino)propanoate (d.r. up to 90 : 10).
在 (5 mol%) 亚胺酸银聚合物和三苯基膦的催化下,通过串联缩醛化/环异构化过程高效地获得了一系列呋喃喹啉类化合物,并通过使用 7 个不同的醇基团实现了多样性。从这些呋喃喹啉中可以得到 3 个还原衍生物(d.r. 高达 94:6),通过杂-Diels-Alder 反应得到 10 种不同的螺酮衍生物(d.r.达 20 : 1),通过与二溴甲醛肟进行环加成反应得到 8 个杂环[5,5]-螺环(d.r. 达 86 : 14),最后通过与 3-溴-2-(羟基亚氨基)丙酸乙酯进行 [4 + 2] 环加成反应得到 6 个杂环[5,6]-螺环(d.r. 达 90 : 10)。