Continuous Flow Synthesis of Quinolines via a Scalable Tandem Photoisomerization‐Cyclization Process

Abstract

A continuous photochemical process is presented that renders a series of quinoline products via an alkene isomerization and cyclocondensation cascade. It is demonstrated that a high-power LED lamp generates the desired targets with higher productivity and efficiency than a medium-pressure Hglamp. The scope of this tandem process is established and al-[a] M.

Scalability of photochemical reactions in continuous flow mode

“…More recently, a variety of new photoreactors designed for continuous processing have been developed. These include commercial systems such as the Vapourtec UV-150 reactor and its high-power LED extension [10][11][12][13][14], the Corning photoreactor system [15][16][17], the Uniqsis PhotoSyn [18,19], or the Firefly system from Cambridge Reactor Design [20]. Furthermore, studies employing a modified rotary reactor (coined PhotoVap) [21], a vortex reactor [22,23] or oscillatory flow reactors for heterogeneous reactions [24,25] have been reported.…”

Ruthenium pincer complex catalyzed efficient synthesis of quinoline, 2-styrylquinoline and quinazoline derivatives via acceptorless dehydrogenative coupling reactions

“…Next, the α,β-unsaturated ketone 9 (ref. 18) was treated under standard conditions to check the mode of cyclization after initial condensation (Scheme 3g). An 89% yield of the corresponding quinoline 4a was obtained which suggests that compound 9 is the possible intermediate for the synthesis of quinoline.…”

Synthesis of 7-Chloroquinoline Derivatives Using Mixed Lithium-Magnesium Reagents

“…Over the past two decades, continuous flow processes have been highlighted as a powerful tool to synthesize natural products, active pharmaceutical ingredients (APIs), − and fragrances . Indeed, a number of quinoline derivatives have been obtained under flow conditions through chlorination, trihalomethylation, and Suzuki–Miyaura arylation . Moreover, microreactor technology has proved its value for the functionalization of several heteroarenes using organometallic intermediates. − …”