01273nas a2200229 4500008004100000022001400041245006800055210006700123260000800190490000700198520059100205653001600796653002300812653001300835653002000848653001400868100001900882700001700901700001800918700001800936856008900954 2023 eng d a1434-193X00aOrganophosphites: an addition to the arsenal of organocatalysts0 aOrganophosphites an addition to the arsenal of organocatalysts cJAN0 v263 a

Organophosphites are nucleophilic in nature and can act as a good leaving group owing to the stability of the phosphite anion. This dual reactivity makes them good candidates for nucleophilic organocatalysis. However, phosphites were introduced only in 2004 as the umpolung catalyst for acylsilane substrates utilizing sequential Brook rearrangements. Very recently, phosphites have been reported to catalyze aza-rearrangements and radical reactions. In this review, we discuss the reactivity parameters to understand its lack of use, as well as the potential for catalysis.

10aacylradical10aazaacyl equivalent10acylanion10aorganocatalysis10aphosphite1 aBaral, Nilofar1 aRani, Soniya1 aSaikia, Pinku1 aMaity, Pradip uhttps://library.ncl.res.in/content/organophosphites-addition-arsenal-organocatalysts02132nas a2200193 4500008004100000022001400041245010900055210006900164260000900233300001600242490000800258520143400266100001901700700001801719700002201737700003001759700001801789856013101807 2026 eng d a0002-786300aMild and site-selective nucleophilic C-H functionalization of pyridines via its stable N-alkylated salts0 aMild and siteselective nucleophilic CH functionalization of pyri cJUN  a22931-229410 v1483 a

Direct, site-selective C-H functionalization of pyridines offers an efficient approach to both streamlined synthesis and late-stage modification of bioactive and functional molecules. Existing approaches to direct nucleophilic substitution typically rely on highly reactive nitrogen-activating groups, which limit nucleophile scope and functional group tolerance and often suffer from poor site selectivity. Although milder activating groups address some of these limitations, they generally require additional installation and removal steps. Herein, we report a mild and general strategy employing designed alkyl halide activators that enables one-pot, site-selective functionalization of pyridines with synthetically valuable yet challenging nucleophiles. This strategy allows, for the first time, direct pyridine functionalization with a broad range of phosphites and amines, in addition to methoxide and cyanide. The mild and redox-neutral reaction conditions are particularly well suited for late-stage functionalization (LSF) of pharmaceutically relevant molecules, enabling site-selective modification with both phosphites and amines. The rational design of the alkyl halide activators, together with careful analysis of side-product formation, reveals the delicate balance required for success with electronically diverse nucleophiles and suggests broader applicability of this C-H functionalization strategy.

1 aBaral, Nilofar1 aSaikia, Pinku1 aMolla, Sabir, Ali1 aDewangan, Devendra, Kumar1 aMaity, Pradip uhttps://library.ncl.res.in/content/mild-and-site-selective-nucleophilic-c-h-functionalization-pyridines-its-stable-n-alkylated