Base-Dependent Divergent Annulation of 4-Chloro-3-formylcoumarin and Tetrahydroisoquinoline: Application to the Synthesis of Isolamellarins and Hydroxypyrrolones
作者:Sameer Vyasamudri、Ding-Yah Yang
DOI:10.1021/acs.joc.8b03259
日期:2019.3.15
coumarin-fused pentacyclic derivatives were synthesized via base-mediated divergent annulation of 4-chloro-3-formylcoumarin and tetrahydroisoquinoline as a key step. This method was then extended to the preparation of isolamellarins A and B (isolamellarin G trimethyl ether). When exposed to UV light, the pyrrolo[2,1-a]isoquinoline- and coumarin-fused pentacycles B were found to undergo aerobic oxidation to give
一系列吡咯并[2,1- a ]异喹啉和香豆素稠合的五环衍生物是通过4-氯-3-甲酰基香豆素和四氢异喹啉的碱介导的发散环化反应合成的,这是关键步骤。然后将该方法扩展到制备异烯丙三醇酯A和B(异麦角菌素G三甲基醚)。当暴露于紫外线下时,发现吡咯并[2,1- a ]异喹啉和香豆素融合的五环B发生有氧氧化,生成相应的羟基吡咯烷酮。
Light/inductive effect induced isomerization of chromeno-5-methyl-2,6,9-trioxabicyclo[3.3.1]nonadienes
作者:Sameer Vyasamudri、Ding-Yah Yang
DOI:10.1039/d0nj02288h
日期:——
Light-mediated [1,3] sigmatropic shift of chromeno-5-methyl-2,6,9-trioxabicyclo[3.3.1]nonadienes to yield chromeno-3-methyl-2,6,9-trioxabicyclo[3.3.1]nonadienes was reported. The migration was observed to proceed without the requirement of UV light if a strong electron-withdrawing group on the benzene moiety or a strong electron-donating group on the coumarin moiety is present. A plausible stepwise