Direct transamidation is gaining prominence as a ground-breaking technique that generates a wide variety of amides without the requirement of acid-amine coupling or other intermediate steps. However, transamidation of unactivated aliphatic amides, on the other hand, has been a long-standing issue in comparison to transamidation of activated amides. Herein, we report a transamidation approach of an unactivated aliphatic amide using a copper catalyst and chlorotrimethylsilane as an additive. In addition, we used transamidation as a tool for selective N-C(O) cleavage and O-C(O) formation to synthesise 2-substituted benzoxazoles and benzothiazoles. The reactions were carried out without using any solvents and offered wide substitution scope.
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http://dx.doi.org/10.1039/d2ob01152b | DOI Listing |
Org Lett
January 2025
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram 695551, Kerala, India.
Herein, we report a formal C-C bond azidation and cyanation of unactivated aliphatic ketones using commercially available tosyl azide and cyanide, respectively. A visible-light-mediated organophotocatalyst enables radical azidation and cyanation of ketone-derived pro-aromatic dihydroquinazolinones (under mostly redox-neutral conditions) as supported by preliminary mechanistic studies. These metal-free and scalable protocols can be used to synthesize tertiary, secondary, and primary alkyl azides and nitriles with good functional group tolerance and postsynthetic diversification of the azide group, including bioconjugation.
View Article and Find Full Text PDFOrg Lett
December 2024
Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021, Japan.
Chemistry
November 2024
Frontiers Science Center for Transformative Molecules, Zhangjiang Institute for Advanced Study, and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
The daunting challenges in converting alcoholic O-H bonds with high bond-dissociation energy (BDE) to alkoxy radicals and harnessing those unruly reaction species largely limit exploiting free alcohols in C(sp)-H functionalization. Herein we describe a novel radical alkynylation and allylation of unactivated C(sp)-H bonds with unmodified aliphatic alcohols. The use of phenyliodine bis(trifluoroacetate) (PIFA) enables the formation of alkoxy radicals under mild photochemical conditions.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Chemistry and Materials Science, Hebei University, Baoding 071002, China.
J Am Chem Soc
October 2024
School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia.
The direct coupling of alkene feedstocks with aldehydes represents an expedient approach to the generation of new and structurally diverse C(sp)-hybridized alcohols that are primed for elaboration into privileged architectures. Despite their abundance, current disconnection strategies enabling the direct coupling of carbon-carbon π-bonds and aldehydes remain challenging because contemporary methods are often limited by substrate or functional group tolerance and compatibility in complex molecular environments. Here, we report a coupling between simple alkenes, heteroarenes and unactivated aliphatic aldehydes via an electrochemically induced reductive activation of C-C π-bonds.
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