Assembly of Highly Functionalized Allylic Sulfones via a Stereoselective Pd‐Catalyzed Sequential C−C/C−S Cleavage and C−S Formation Process

Abstract

A Pd-catalyzed sequential CÀ C/CÀ S cleavage and CÀ S formation approach for highly functionalized allylic sulfones synthesis of vinylcyclopropanes with p-tosylmethyl isocyanide has been developed under mild conditions. Importantly, the reaction of modular VCPs and TosMIC would give access to (E)-allylic sulfones in a stereoselective and regioselective fashion onto the in situ formed Pd intermediate. The current protocol featured broad substrate scope, operational convenience, and gram-scale production.Organosulfur compounds such as sulfones and thioethers are versatile in synthetic chemistry, and have found diverse applications in agrichemicals, pharmaceuticals, and materials science. [1,2] In particular, allylic aryl sulfones exhibit a variety of pharmacological properties, including antifungal, antitumor, anti-inflammatory, and anti-HIV activities, [3] and their derivatives are representative in top 200 brand name drugs by retail dollars (Scheme 1a). [4] The traditional synthetic methods to these sulfones, as we all know, typically involve direct oxidation of sulfides, [5] hydrothiolation of alkynes or allenes, [6] allylic substitution with sulfonyl halides [7] and CÀ H bond functionalization. [8] Despite the impressive progress noted in this area, the related synthesis have limited applications because of undesirable side reactions and poor stereochemical control, and the general catalytic methodology for the stereoselective synthesis of highly substituted allylic sulfones remains rarely developed. It is thus highly imperative to explore a practical strategy to access allylic sulfone and its derivatives. Recently, Breit and coworkers reported a Rh-catalyzed hydrothiolation strategy for the (Z)-selective preparation of a diverse series of sulfones (Scheme 1b). [9] Soon afterwards, a (Z)-selective allylic sulfones synthesis was reported by Kleij [10] and Chen [11] using decarboxylative functionalization of vinyl carbonates under Pd catalysis (Scheme 1c).

Synergetic effects of a poly-tartrazine/CTAB modified carbon paste electrode sensor towards simultaneous and interference-free determination of benzenediol isomers

“…The detection limit for HQ at the poly-TZ/CTAB/MCPE was found to be 0.41 × 10 −6 M, which is better than the reported detection limits for other modified electrodes and electrochemical methods listed in Table 2. 35,52,56–69…”

“…The method implemented in this study was more effective than other documented methods. 35,52,[56][57][58][59][60][61][62][63][64][65][66][67][68][69] 3.8. The effect of pH variation for the determination of CC at the poly-TZ/CTAB/MCPE…”

“…The detection limit for HQ at the poly-TZ/CTAB/MCPE was found to be 0.41 × 10 −6 M, which is better than the reported detection limits for other modified electrodes and electrochemical methods listed in Table 2. 35,52,[56][57][58][59][60][61][62][63][64][65][66][67][68][69] 3.11. The effect of solution pH variation on the oxidation of HQ at the poly-TZ/CTAB/MCPE The electrochemical oxidation of 0.1 mM HQ at the poly-TZ/ CTAB/MCPE was analyzed using cyclic voltammetry to investigate the effect of varying pH values.…”