The Thionium/N-Acyliminium Ion Cyclization Cascade as a Strategy for the Synthesis of Azapolycyclic Ring Systems
作者:Albert Padwa、Alex G. Waterson
DOI:10.1016/s0040-4020(00)00861-9
日期:2000.12
thiophenyl lactams with BF3·2AcOH which resulted in the generation of an N-acyliminium ion. Cyclization of the iminium ion onto the tethered aromatic ring led to various azapolycyclic ring systems. A related cyclization sequence also occurred with amidosulfoxides that possess simple olefinic tethers. The method was applied toward the synthesis of a member of the protoberberine alkaloid family.
通过将苯硫酚加到适当的链烯酸π键上,制备了一系列的氨基亚砜,随后使原位生成的酰氯与3,4-二甲氧基苯乙胺反应。在催化量的ZnI 2存在下,使用1-(二甲基-叔丁基甲硅烷氧基)-1-甲氧基乙烯在干燥的乙腈中进行硅诱导的这些氨基亚砜的Pummerer反应,并导致非常干净地形成2-硫代苯基取代的内酰胺。通过用BF 3 ·2AcOH处理最初形成的硫代苯基内酰胺,可实现亚胺离子芳族π-环化反应,从而产生N-酰亚胺离子。亚胺离子在束缚的芳香环上的环化导致各种氮杂多环系统。具有简单烯烃系链的氨基亚砜也发生了相关的环化顺序。该方法用于原小ber碱生物碱家族成员的合成。