The mechanism of Sandmeyer's cyclization reaction by electrospray ionization mass spectrometry

Abstract

Using electrospray ionization (tandem) mass spectrometry (ESI-MS(/MS)) spectrometric experiments, the Sandmeyer reaction was monitored on-line, and key intermediates were intercepted and characterized for the first time. The mechanistic information provided by on-line ESI-MS(/MS) is in accordance with Sandmeyer's proposal, and was made possible by coupling a microreactor on-line to the ESI ion source, which allowed reactions to be screened from 0.7-2.0 s, identifying and characterizing all intermediates that were formed and consumed during the reaction.

Online Monitoring of Polymerizations: Current Status

“…Mostly the mixing tee is connected to the ionization probe with a fused-silica capillary providing residence times from 0.7 to 28 s in a continuous flow mode by varying the length of the transfer capillary. [66][67][68][69][70][71][72] Continuous online MS monitoring of polymerization reactions was first made available by Santos and Metzger. They investigated the mechanism of the homogeneously catalyzed Ziegler-Natta polymerization of ethane and Brookhart polymerization of alkenes in early stages of the polymerization.…”

The Isatins of Professor Angelo

“…10 Na literatura encontram-se duas propostas de mecanismos: a proposta de Sandmeyer, na qual ocorre a formação do intermediário 7 (caminhos a e b), e a proposta de Piozzi e Favini, com a formação dos intermediários 8, 9 e 10 (caminhos c, d e e). Segundo estes autores, o intermediário 9 encontra-se em equilíbrio, via tautomerismo, com o intermediário 10 (caminho f) e produz a imina 7 (caminho e), como ilustrado no Esquema 3.…”

What do we know about reaction mechanism? the electrospray ionization mass spectrometry approach

“…50,51 This account may serve to show the significant innovative potential of ESI-MS for the investigation of reaction mechanisms of organic and organometallic reagents in the gas phase. It is exemplified herein the usage of the ion/molecule reactions to probe the catalyst activity of different species intercepted in condensed phase, a straightforward method not available so far.…”