Pd-Catalyzed sp3 C–H alkoxycarbonylation of 8-methylquinolines using Mo(CO)6 as a CO surrogate

2021 ◽  
Vol 57 (27) ◽  
pp. 3359-3362
Author(s):  
Kangkan Talukdar ◽  
Tanumay Sarkar ◽  
Subhasish Roy ◽  
Tharmalingam Punniyamurthy
Keyword(s):  
Natural Product ◽  
Functional Group ◽  
Product Modification

Pd(ii)-Catalyzed three-component sp3 C–H alkoxycarbonylation of 8-methylquinonlines is developed using Mo(CO)6 as a CO source with the substrate scope, functional group tolerance and natural product modification.

scholarly journals Intermolecular 3+3 Ring Expansion of Aziridines to Dehydropiperidines through the Intermediacy of Aziridinium Ylides

2019 ◽  
Author(s):  
Jennifer Schomaker ◽  
Josephine Eshon ◽  
Kate A. Nicastri ◽  
Steven C. Schmid ◽  
William T. Raskopf ◽  
...  
Keyword(s):  
Natural Product ◽  
Functional Group ◽  
Ring Expansion ◽  
Sigmatropic Rearrangement ◽  
Reactive Intermediate ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Complex Molecules ◽  
Form Complex ◽  
Reaction Proceeds

Bicyclic aziridines undergo formal [3+3] ring expansion reactions when exposed to rhodium-bound vinyl carbenes to form complex dehydropiperidines in a highly stereocontrolled rearrangement. Mechanistic studies and DFT computations indicate the reaction proceeds through the formation of a vinyl aziridinium ylide; this reactive intermediate undergoes a concerted, asynchronous, pseudo-[1,4]- sigmatropic rearrangement to directly furnish the heterocyclic products with net retention at the new C-C bond. In combination with an asymmetric silver-catalyzed aziridination developed in our group, this method quickly delivers enantioenriched scaffolds with up to three contiguous stereocenters. The mild reaction conditions, functional group tolerance, and high stereochemical retention of this method are especially well-suited for appending piperidine motifs to natural product and complex molecules. Ultimately, our work establishes the value of underutilized aziridinium ylides as key intermediates in strategies to convert small, strained rings to larger N-heterocycles.

scholarly journals 3-Bromotetrazine: A Versatile Precursor for the Synthesis of 3-Monosubstituted s-Tetrazines and the Labelling of Macromolecules

2019 ◽  
Author(s):  
Simon Schnell ◽  
Lukas Hoff ◽  
Advaita Panchagnula ◽  
Simon Sieber ◽  
Anthony Linden ◽  
...  
Keyword(s):  
Natural Product ◽  
Mammalian Cells ◽  
Functional Group ◽  
Aqueous Media ◽  
Diels Alder ◽  
The Novel ◽  
Chemical Probe ◽  
Complex Molecules ◽  
Inverse Electron Demand ◽  
Electron Demand

<div><div><div><p>We report the synthesis of the novel precursor 3-bromotetrazine and its successful use in the synthesis of various families of 3-monosubstituted s-tetrazines. A remarkable functional group selectivity is utilized to site-selectively functionalize different complex molecules. The unexpected stability of 3- bromotetrazine in aqueous media facilitated the development of a protocol for protein functionalization in- stalling a tetrazine unit as a bio-orthogonal handle for inverse electron demand Diels-Alder reactions. Addi- tionally, a novel tetrazine-based chemical probe was developed and its application in the context of thiol- targeted natural product isolation and labelling of mammalian cells is demonstrated.</p></div></div></div>

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