Simple Efficient Synthesis of Pyranoquinoline Alkaloids: Flindersine, Khaplofoline, Haplamine and their Analogues
作者:Dhanabal Thangavel、Sangeetha Ravindran、Gengan Robert Moonsamy、Mohan Subramaniam Palathurai
DOI:10.3184/030823407x191859
日期:2007.2
An efficient two step synthesis of pyranoquinoline alkaloids is described. Direct treatment of isoprene with 4-hydroxyquinolin-2(1H)-one in the presence of polyphosphoric acid furnished dihydroflindersine in good yield, and which on dehydrogenation led to a newsynthesis of flindersine. Khaplofoline, a linear pyranoquinoline alkaloid, was obtained as a minor product. The syntheses of derivatives are
An acid‐catalyzed regiodivergentannulation of biomass‐derived 4‐hydroxycoumarins with isoprene is developed, providing a facile access to pyranocoumarins and pyranochromones.
Isoprene: A Promising Coupling Partner in C–H Functionalizations
作者:Qing-An Chen、Wei-Song Zhang、Yan-Cheng Hu
DOI:10.1055/s-0040-1707172
日期:2020.10
basic industrial feedstock isoprene is an ideal alternative precursor. However, given that electronically unbiased isoprene might undergo six possible addition modes in the coupling reactions, it is difficult to control the selectivity. This article summarizes the strategies we have developed to achieve regioselective C–H functionalizations of isoprene under transition-metal and acid catalysis. 1 Introduction