Synthesis spiro and fused chromenes via [4 + 2] cycloaddition of salicyl N-tosylimines and cyclic dienophiles
作者:Xing Liu、Daqian Wang、Jing Sun、Chao-Guo Yan
DOI:10.1016/j.molstruc.2024.137684
日期:2024.5
forward synthetic protocol for spiro and fused chromenes has been developed by base promoted oxa-Michael/Mannich reaction of salicyl N-tosylimines and various cyclic dienophiles. 1,4-diazabicyclo[2.2.2]octane (DABCO) promoted [4 + 2] cycloaddition reaction of salicyl N-tosylimines and 3-methyleneoxindoles or 2-arylidene-1,3-indanediones in THF at room temperature afforded functionalized spiro[chromane-3,3′-indolines]
通过水杨酰 N-甲苯磺酰亚胺和各种环状嗜二烯烃的碱促进 oxa-Michael/Mannich 反应,开发了一种直接的螺和熔融铬合成方案。1,4-二氮杂双环[2.2.2]辛烷 (DABCO) 在室温下促进水杨基 N-甲苯磺酰亚胺和 3-亚甲基氧吲哚或 2-芳基-1,3-茚二酮在 THF 中的[4 + 2]环加成反应,得到功能化螺[色烷-3,3′-吲哚啉]或螺[chromane-3,2′-inden]-1′,3′-二酮,中等至良好产率和高非对映选择性。另一方面,水杨酰 N-甲苯磺酰亚胺和 5,6-未取代的 1,4-二氢吡啶的类似 [4 + 2] 环加成反应导致四氢铬基 [3,2-b] 吡啶衍生物的产率令人满意。