Recent advances of Ritter reaction and its synthetic applications

Abstract

In comparison to previous reviews, the present review article provides a comprehensive survey of Ritter reactions from 2014 to 2020, mainly aiming to discuss diverse Ritter reactions and their widely...

Catalytic Cycloisomerization of Enyne Diesters Derived From 2‐Propargyloxyarylaldehydes

“…In the case of substrate 8 n , the vinyl‐carbocation may isomerize to generate more stable alkyl‐carbocation leading a complex reaction mixture. The vinyl carbocation can be intercepted via Ritter type reaction [27] by carrying out the reaction in dry acetonitrile as the solvent to generate compound 14 stereoselectively (Scheme 5b), suggesting a non‐concerted stepwise reaction pathway. The Z ‐stereochemistry of compound 14 was assigned based on 2D NOESY experiment (page S18, Supporting Information).…”

Syntheses of Aristotelia Alkaloids: Reflections in the Chiral Pool

“…[11][12][13] Because of the large excess of nitrile used in these reaction, the penultimate carbocation intermediate is intercepted by a second equivalent of the aryl nitrile, which upon hydrolysis of the resulting nitrilium is converted into the amide in 17. In addition to 6 and 9, other monocyclic terpenes like (+)-limonene (18), -terpineol (19), and terpinolene (20) gave rise to 17. Furthermore, even acyclic monoterpenes including geraniol and nerol are also viable substrates for the reaction, presumably by first undergoing an acid-mediated cyclization to generate 16.…”

“…Although the Ritter-like reaction with monoterpenes has provided general, rapid access to the Aristotelia alkaloid scaffold, this approach is not without its shortcomings. [16][17][18] Both the mercury-and Brønsted acid mediated reactions typically employ a large excess of the nitrile, which may not always be economically or synthetically feasible. Also, as highlighted in Scheme 3, terpenes are notoriously prone to acid-catalyzed rearrangements giving rise to various isomeric byproducts.…”

Discovery of New Ginsenol-Like Compounds with High Antiviral Activity

“…Due to the high importance of this bond, there are many methodologies for creating an amide bond. Among the widely known methods, the Ritter reaction, a method for the synthesis of N-substituted amides of carboxylic acids by alkylation of nitriles with carbocations, occupies a special position [38]. Under acid catalysis, alkenes or their derivatives, alcohols, oxiranes, etc., can act as carbocation precursors [39].…”