Ruthenium(II)‐Catalyzed Hydrogen Transfer/Annulation Cascade Processes between Alcohols and 2‐Nitrobenzaldehydes

Abstract

The synthesis of quinolines from alcohols and 2‐nitrobenzaldehydes is described. Unreactive alcohols and 2‐nitrobenzaldehydes were concurrently converted to the reactive reactants for a Friedländer annulation via a hydrogen transfer. Tris(triphenylphosphine)ruthenium(II) dichloride [Ru(PPh3)3Cl2] appeared to serve the dual role of an efficient hydrogen transfer catalyst and a suitable Friedländer annulation catalyst.magnified image

Divergent Synthesis of Bioactive Marine Meroterpenoids by Palladium‐Catalyzed Tandem Carbene Migratory Insertion

“…In connection with our previous work, we wanted to continue our research into the divergent synthesis of biologically active marine meroterpenoids starting from readily available (+)‐sclareolide ( 9 ) ,. [15d], …”

A review on transition-metal mediated synthesis of quinolines

“…The catalyst serves the dual role of catalyzing both the transfer hydrogen reaction and Friedlander annulation. 60 An inexpensive, sustainable and air-stable, combo CuSO 4 -D-glucose catalyst system was developed by Anand and colleagues for the synthesis of functionalized quinoline via modified Friedlander approach (Scheme 32). The developed route was based on the domino multi-component approach which directly leads to the construction of substituted quinolines (105) from 2-bromoaromatic aldehydes/ketones (104) using H 2 O-EtOH as green solvent.…”

Synthesis of multi‐functionalized quinolines and 1,2‐dihydroquinolines through FeCl3‐mediated reactions of carbonyl compounds with 2‐vinylanilines

“…Nevertheless, the majority of these methods suffer from drawbacks such as strong acidic or basic conditions, high reaction temperatures, long reaction times, excessive oxidants, low regioselectivities, and so on. In recent decades, significant progress has been made in the development of transition‐metal‐catalyzed methods such those using iridium, rhodium, ruthenium, palladium, nickel, gold, silver, copper, and iron because of their functional group tolerance, stero‐ and regioselectivity, and excellent yields under mild reaction conditions. Although these procedures provide efficient routes for assembling the quinoline skeleton, most of them use expensive and often toxic metal catalysts, which often generate heavy metal impurities in the product and limit their large‐scale applications.…”