1569019-04-0Relevant articles and documents
Continuous Flow Synthesis and Purification of Aryldiazomethanes through Hydrazone Fragmentation
Lévesque, éric,Laporte, Simon T.,Charette, André B.
, p. 837 - 841 (2017/01/14)
Electron-rich diazo compounds, such as aryldiazomethanes, are powerful reagents for the synthesis of complex structures, but the risks associated with their toxicity and instability often limit their use. Flow chemistry techniques make these issues avoidable, as the hazardous intermediate can be used as it is produced, avoiding accumulation and handling. Unfortunately, the produced stream is often contaminated with other reagents and by-products, making it incompatible with many applications, especially in catalysis. Herein is reported a metal-free continuous flow method for the production of aryldiazomethane solutions in a non-coordinating solvent from easily prepared, bench-stable sulfonylhydrazones. All by-products are removed by an in-line aqueous wash, leaving a clean, base-free diazo stream. Three successful sensitive metal-catalyzed transformations demonstrated the value of the method.
Improved zinc-catalyzed simmons-smith reaction: Access to various 1,2,3-trisubstituted cyclopropanes
Levesque, Eric,Goudreau, Sebastien R.,Charette, Andre B.
supporting information, p. 1490 - 1493 (2014/04/03)
The Simmons-Smith reaction of zinc carbenoids with alkenes is a powerful method to access cyclopropanes containing various substitution patterns. This work exploits the high reactivity of aryldiazomethanes toward zinc halides to generate aryl-substituted carbenoids catalytically. These carbenoids are able to cyclopropanate various alkenes diastereoselectively, including unfunctionalized substrates such as styrenes. The zinc catalyst can be modified to tolerate the use of free allylic alcohols.
