可见光诱导烯烃去芳香化成环合成含氟氮杂螺环已二烯酮

发展了一种可见光诱导的N-苄基丙烯酰胺去芳香化成环合成多氟烷基化氮杂螺环已二烯酮的反应。 此反应以多氟烷基碘或溴为自由基源,以fac-Ir(ppy)₃(fac:面式;ppy:2-苯基吡啶)作为光催化剂,在发光二极管(LED)蓝光灯照射条件下,使N-丙烯酰基-N-苄基苯甲酰胺串联自由基加成/去芳香化环合,合成了一系列含氟氮杂螺环已二烯酮类化合物,产率为61%~85%。 值得提出的是,此反应能快速在氮杂螺环已二烯酮骨架上引入多种多氟烷基基团如CF₃I、C₃F₇I、C₄F₉I、C₆F₁₃、C₈F₁₇I、CH₂CF₂I和BrCF₂CO₂Et(Et:乙基)等,且底物适用范围广、反应条件温和(室温)、催化体系绿色,为具有潜在药用价值和生理活性的多氟烷基化氮杂螺环已二烯酮的合成提供了一条高效、快捷的新途径。

Visible-Light-Induced Dearomatizing Spirocyclization of Alkenes Toward Perfluorinated Azaspirocyclic Cyclohexadienones

A visible-light-induced dearomation cyclilation of N-benzylmethacrylamides with nonafluorinated alkyl bromides or iodides toward nonafluorinated azaspirocyclic cyclo-hexadienones was developed. Under the irradiation of blue light-emitting diode(LED) light, using fac-Ir(ppy)₃(fac=facial, ppy=2-phenylpyridyl) as the photocatalyst, N-benzylmethacrylamides and nonafluorinated alkyl bromides or iodides underwent cascade dearomation/cyclilation under optimal conditions, leading to a series of perfluorinating azaspirocyclic cyclohexadienones in 61%85% yield, as well as introducing a series of perfluorinated moieties including CF₃, C₃F₇, C₄F₉, C₆F₁₃, C₈F₁₇, CH₂CF₂, CF₂CO₂Et(Et:Ethyl). Given the broad substrate scope, mild reaction conditions and green catalytic systems, this protocol provides a green, effective and quick approach to pharmaceutically important cyclohexadienones.