The functionalization of C À Hb onds with nonprecious metal catalysts is an important researcha rea for the development of efficient and sustainable processes.Herein, we describe the development of iron porphyrin catalyzedreactions of diazoacetonitrile with N-heterocycles yielding important precursors of tryptamines,a long with experimental mechanistic studies and proof-of-concept studies of an enzymatic process with YfeX enzyme.B yu sing readily available FeTPPCl, we achieved the highly efficient CÀHfunctionalization of indole and indazole heterocycles.T hese transformations feature mild reaction conditions,e xcellent yields with broad functional group tolerance,c an be conducted on gram scale,a nd thus provide au nique streamlined access to tryptamines.
The reductive cross coupling of pyridinium salts derived from readily available primary alkyl amines with aryl halides has been achieved under mild reaction conditions using a nickel catalyst.
A novel continuous-flow approach for the synthesis of fluoroalkyl-substituted diazomethanes has been developed. Utilizing a cheap, self-made microreactor fluoroalkyl-substituted amines were transformed into the corresponding diazomethanes using tert-butyl nitrite and acetic acid as catalyst. These diazomethanes were employed in [2+3] cycloaddition reactions with olefins and alkynes, yielding valuable pyrazolines and pyrazoles in good to excellent yields.
Out of bounds: Enantioselective rearrangement reactions are a long-standing challenge in organic synthesis. Recent advances are highlighted that led to the development of the first enantioselective Doyle-Kirmse reaction and enantioselective rearrangement reactions of iodonium ylides.
Toxic, cancerogenic and explosive-these attributes are typically associated with diazo compounds. Nonetheless, diazo compounds are nowadays a highly demanded class of reagents for organic synthesis, yet the concerns with regards to safe and scalable transformations of these compounds are still exceptionally high. Lately, the research area of the continuous-flow synthesis of diazo compounds attracted significant interest and a whole variety of protocols for their "on-demand" preparation have been realized to date. This concept article focuses on the recent developments using continuous-flow technologies to access diazo compounds; thus minimizing risks and hazards when working with this particular class of compounds. In this article we discuss these concepts and highlight different pre-requisites to access and to perform downstream functionalization reaction.
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