Pyridyl sulfonyl group

Sulfones are an appealing class of substrates and have been used in tandem reactions with generation of a chiral center a to the sulfonyl group (Scheme 54) [148]. In order to achieve bidentate chelation with metal, pyridyl... 

Another interesting reaction of sulfonylpyridines is with f-BuOK in CH2CI2, in which even a bulky alkoxide such as f-BuOK substitutes the sulfonyl group to give 2-r-butoxypyridine in substantial yield together with (6 -chloro-2 -pyridylmethyl)-6-chloro-2-pyridyl sulfone. The formation of this sulfone is accounted for by the initial formation of the sulfonyl carbanion which reacts further with the starting sulfone to afford the product [reaction (27)] (82UP2). This reaction also demonstrates that even a... 

On reaction with amines R NHR2, only the AE (reaction sequence A) with C—O bond scission will lead to animation product 37 and sulfonic acid 38, whereas the competing attack on the sulfonyl group (reaction sequence B) with S—O bond scission will lead to 2-(l//)-pyridinone (27) and a sulfonamide 39, thus decreasing the yield of the desired amination product (cf. 209 — 210 in Section IV,E). This B-type of scission is also common for other leaving groups. Thus, derivatives of 2-(l//)-pyridinone (27), such as bis(2-hydroxy-pyridyl)-carbonate, are used as activated de-rivates of carbon dioxide in the presence of 4-dimethylaminopyridine (DMAP) (880PP145). 

It was independently reported by Gomez Arrayas and Carretero [22] and by Zhang [23] that a (2-pyridyl)sulfinyl group is utiUzable as a removable directing group to induce regioselective alkenylation (Scheme 18.23). Gomez Arrayas and Carretero [24] also reported a similar alkenylation of N-(2-pyridyl)sulfonyl anilines (Scheme 18.24). 

Arrayayas and Carretero employed a Af-(2-pyridyl)sulfonyl protecting group to assist in their palladium(II)-catalyzed C2 alkenylation of pyrrole, whereas the research groups of Li and Wang used a A, A-dimethylcarbamoyl group to affect alkenylation of pyrrole at the C2 position under rhodium-catalyzed conditions. ... 

In 2011, Carreetero et al. verified that A-(2-pyridyl)sulfony was an easily introduced and removable directing group preliminary results on C(sp )-H bond functionalization was disclosed using this new auxiliary [34]. As their follow-up work, they later reported A-(2-pyridyl)sulfonyl-directed y-C(sp )-H arylation [35]. A series of simple amino acid methyl esters and amides were able to dehver highly selective yatyl ted products under optimal conditions (Scheme 1.13). The... 

Carretero and coworkers [24] developed an easily installed and removable AI-(2-pyridyl) sulfonyl directing group and thereafter demonstrated its successful appUcation in the... 

A rearranged / abnormal Barton-Zard Pyrrole product is observed when the protecting group on nitrogen is phenyl sulfonyl. However, when R = Bn, C02Et or 2-pyridyl, the expected pyrrolo[3,4,h]indole is obtained. 

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