Synthesis of New Sulfonyloximes and Their Use in Free-Radical Olefin Carbo-oximation

Abstract

New bifunctional reagents for free-radical carbo-oximation of olefins have been developed. In this process, a single reagent can act both as a trap for nucleophilic radicals as well as a source of electrophilic radical via an α-scission of an alkylsulfonyl radical. This strategy involving the addition of a C-centered electrophilic radical and an oxime across the double bond of an electron-rich alkene is initiated with a t-BuO radical following an unusual mechanism, supported by both experiments and density functional theory calculations.

Free‐Radical Carbocyanation of Olefins

“…However, such a process would be really useful for synthetic purposes if a tin‐free version were made available, as in certain cases, complete removal of tin residues may be tedious. On the basis of literature precedents, it was intended to develop access to a sulfone such as 20 having both an ester functional group, as in radical precursors 1 a – c , and a cyano substituent (Scheme ). An initiation step should generate electrophilic radical I , the addition of which to the olefin would afford new nucleophilic radical II .…”

Free-radical Carbo-functionalization of Olefins Using Sulfonyl Derivatives

“…Based on precedent from Zard [5a] and Renaud's groups, [26] we devised new bifunctional reagents 26a-e, incorporating both the oxime function and the radical precursor moiety, thus avoiding the use of tin additives. [27] These reagents act both as traps for nucleophilic radicals as well as sources of electrophilic radicals via the α-scission of the alkylsulfonyl radical intermediates. This reversible α-scission, [28] relatively easy with alkylsulfonyl species, based on the carbo-azidation of olefin 30, which afforded the key intermediate 31 in good yield, albeit with poor stereocontrol and efficient synthesis of pyrrolizidine and indolizidine alkaloid skeleton.…”

Highly Efficient One‐Step Synthesis of N‐Trimethylsiloxy Alkyl Imidothioates

“…There are three classes of compounds that contain the N–OH bond: hydroxylamines (R 2 N–OH), oximes (R 2 C=N–OH), and hydroxamic acids (RCONH–OH) Oximes and their analogues alkyl imidothioates are highly important reagents in many of organic transformations, and these structural motifs are known for their biological activity . In spite of the many methods that have been developed for their synthesis, there are a lack of examples that involve the direct use of thiols to obtain alkyl imidothioates.…”

“…that have been developed for their synthesis, [19][20][21][22][23] there are a lack of examples [24] that involve the direct use of thiols to obtain alkyl imidothioates.…”