A palladium-catalyzed [2 + 2 + 1] domino annulation of 3-iodochromones, α-bromo carbonyl compounds, and tetracyclododecene (TCD) is described. This approach provides a facile, efficient and atom-economical route to a variety of chromone-containing polycyclic compounds bearing fused/bridged-ring systems in good yields (up to 81%) with excellent diastereoselectivities (99 : 1 dr in all cases).
A palladium-catalyzedthree-component [2 + 3 + 1] domino annulation among 3-iodochromones, α-bromoacetophenones, and norbornene is presented, affording various chromone-containing polycyclic compounds bearing fused/spiro/bridged-ring systems. For the first time, the 2,2-bifunctionalization of norbornene was realized in palladium-catalyzeddominoreaction. This cyclization characterizes three new bonds
palladium‐catalyzed [2+2+1] annulation among 3‐iodochromones, benzyl bromides, and norbornene has been developed. This annulation consists of a domino sequence involving Heck coupling/C(sp2)−Hactivation/C(sp3)−Hactivation, affording a variety of complex chromone derivatives bearing five contiguous tertiary carbon centers in up to 94% yield and 99:1 dr. Interestingly, the diastereoselectivity could be
Synthesis of 3-halochromones with simple KX halogen sources enabled by <i>in situ</i> halide oxidation
作者:Yan Lin、Jie-Ping Wan、Yunyun Liu
DOI:10.1039/d0nj00825g
日期:——
On the basis of a designated in situ oxidation tactic, the synthesis of 3-halochromones has been realized for the first time by using simple KX (X = Br, I) salts as halogen sources. Instead of the free radical process, the control experiments indicate that the reported reactions proceed through a halogenium intermediate. Compared to the known synthetic methods relying on molecular halogen, haloid acid
Photoredox Functionalization of 3-Halogenchromones, 3-Formylchromones, and Chromone-3-carboxylic Acids: Routes to 3-Acylchromones
作者:Satenik Mkrtchyan、Viktor O. Iaroshenko
DOI:10.1021/acs.joc.0c00537
日期:2020.6.5
describes a set of new and efficient syntheticroutes toward 3-acyl-substituted chromones ranging from readily available chromone precursors, namely 3-halogenchromones, 3-formylchromones, and chromone-3-carboxylic acids by means of visible-light photoredox catalysis. The operationally simple protocols transform a wide variety of chromone derivatives into challenging 3-acyl-substituted chromones in excellent