Controlled Release of Reactive Gases: A Tale of Taming Carbon Monoxide

Abstract

This Personal Account describes the development of air‐stable and solid precursors for on‐demand release of carbon monoxide. In combination with the development of a two‐chamber reactor, COware®, CO liberation can be achieved under safe working conditions, as well as allowing transition metal‐mediated carbonylations with stoichiometric carbon monoxide. Particularly appealing is the adaptability of this chemical technology for the preparation of carbon isotope labeled bioactive compounds.

Diastereoselective Synthesis of N-Methylspiroindolines by Intramolecular Mizoroki–Heck Annulations

“… 28 The reaction was run in a two-chamber system, where one chamber is dedicated to the in situ production of carbon monoxide from Mo(CO) 6 , which can then diffuse to the other chamber where the carbon monoxide-consuming benzyloxycarbonylation can occur. 29 , 30 Employing these conditions, the C- and N-protected unnatural amino acid 10 was synthesized and isolated in 64% yield.…”

“…In order to access the benzyl-protected C-terminal end of our desired unnatural amino acid, aryl bromide 9k was subjected to a palladium-catalyzed benzyloxycarbonylation with a PdOAc 2 :XantPhos catalytic system (Scheme ). The reaction was run in a two-chamber system, where one chamber is dedicated to the in situ production of carbon monoxide from Mo­(CO) 6 , which can then diffuse to the other chamber where the carbon monoxide-consuming benzyloxycarbonylation can occur. , Employing these conditions, the C- and N-protected unnatural amino acid 10 was synthesized and isolated in 64% yield.…”

Practical Gas Cylinder-Free Preparations of Important Transition Metal-Based Precatalysts Requiring Gaseous Reagents

“…Our group has a longstanding interest in enabling the use of small gaseous molecules by stoichiometric ex situ release of gaseous reagents from easy-to-handle precursors in two- or three-chamber reactors. We have reported the utilization of hydrogen, , carbon monoxide, − ethylene, methanethiol, and hydrogen cyanide in this manner, establishing the application of specialized gas precursors for chemical synthesis and isotope labeling. De Borggraeve et al have also demonstrated the utility of the two-chamber reactor for sulfuryl fluoride generation .…”

A Fluorogenic ONOO–-Triggered Carbon Monoxide Donor for Mitigating Brain Ischemic Damage

“…CO donors are safer alternatives and have potential for drug development . A plethora of CO-releasing molecules have been reported, including carbonyl–metal complexes and triggered CO donors . Recently, Choi et al reported neuroprotective effects of CO during I/R …”