271769-81-4Relevant articles and documents
Reaction Cycling for Kinetic Analysis in Flow
Newman, Stephen G.,Sullivan, Ryan J.
supporting information, p. 5464 - 5474 (2020/05/19)
A reactor capable of efficiently collecting kinetic data in flow is presented. Conversion over time data is obtained by cycling a discrete reaction slug back and forth between two residence coils, with analysis performed each time the solution is passed between the two. In contrast to a traditional steady-state continuous flow system, which requires upward of 5× the total reaction time to obtain reaction progress data, this design achieves much higher efficiency by collecting all data during a single reaction. In combination with minimal material consumption (reactions performed in 300 μL slugs), this represents an improvement in efficiency for typical kinetic experimentation in batch as well. Application to kinetic analysis of a wide variety of transformations (acylation, SNAr, silylation, solvolysis, Pd catalyzed C-S cross-coupling and cycloadditions) is demonstrated, highlighting both the versatility of the reactor and the benefits of performing kinetic analysis as a routine part of reaction optimization/development. Extension to the monitoring of multiple reactions simultaneously is also realized by operating the reactor with multiple reaction slugs at the same time.
Overcoming solid handling issues in continuous flow substitution reactions through ionic liquid formation
Kashani, Saeed,Sullivan, Ryan J.,Andersen, Mads,Newman, Stephen G.
supporting information, p. 1748 - 1753 (2018/04/30)
Substitutions such as acylations, arylations, and alkylations are some of the most commonly run reactions for building complex molecules. However, the requirement of a stoichiometric base to scavange acid by-products creates significant challenges when operating in continuous flow due to solid handling issues associated with precipitating base·HX salts. We present a general and simple strategy to overcome these solid handling issues through the use of acid scavenging organic bases that generate low- to moderate-melting ionic liquids upon protonation. The application of these bases towards the most commonly run substitutions are demonstrated, enabling reactions to be run in flow without requiring additional equipment, specific solvents, or dilute reaction conditions to prevent clogging.
Phase-Transfer Catalyzed O-Silyl Ether Deprotection Mediated by a Cyclopropenium Cation
Mir, Roya,Dudding, Travis
, p. 709 - 714 (2017/04/26)
The use of a cyclopropenium cation as a phase-transfer catalyst for O-silyl ether deprotection is reported. Mechanistic insight into this deprotection methodology derived by linear free-energy relationships (LFER), quantum theory of atoms in molecules (QTAIM), and density functional theory (DFT) calculations are also provided.
