Nitro‐Substituted Aryl Lithium Compounds in Microreactor Synthesis: Switch between Kinetic and Thermodynamic Control

Abstract

Beeil Dich oder lass Dir Zeit, je nach dem, was Du willst: Mit einer Mikroflussmethode zur Erzeugung und Umwandlung o‐, m‐ und p‐Nitro‐substituierter Aryllithiumverbindungen konnte selektiv entweder das kinetisch oder das thermodynamisch begünstigte Intermediat genutzt werden. Im gezeigten Beispiel entstand bei einer Verweildauer von 0.06 s bei −48 °C 1, während eine Verweildauer von 63 s ausschließlich 2 ergab.

Scale-up concept of single-channel microreactors from process development to industrial production

“…Rapid mixing and correct control of the stoichiometry also avoids consecutive-competitive reactions. Typical reactions are of cryogenic type such as organometallic reactions [10][11][12][13][14]. • Type B reactions are rapid in the range of several minutes (<10 min), but mixing in microchannels is always faster.…”

“…(4), (6), (10), and (13) guide the proper and consistent design of microchannel reactors for flow velocity, Re number, pressure drop, and mixing time. The internal channel size and channel cross-section area are also growing with plate size allowing higher flow rates through the reactor, see Fig.…”

A flow-microreactor approach to protecting-group-free synthesis using organolithium compounds

“…2b, see also Supplementary Table S1). However, acceptable yields were not obtained even at the minimum limit of the residence time of our current system (0.01 s), although this residence time was successful for the generation of alkoxycarbonyl- 44 , nitro- 45 and cyano-substituted 46 aryllithiums. Aryllithium 2 bearing a ketone carbonyl group decomposed very rapidly, the major by-product being dimeric compound 4.…”

Synthesis of Organometallic Compounds in Flow

“…This methodology was then generalized to the functionalization of p ‐ and m ‐dibromobenzenes, and bromobenzenes substituted with different reactive groups such as esters, carbamates or carbonates, cyano and nitro or heteroaromatic systems such as dibromopyridines …”