Diethyl phosphite-mediated switchable synthesis of bis(imidazoheterocycles) derived disulfanes and sulfanes using imidazoheterocycles and octasulfur

Abstract

A practical and highly efficient oxidative dual C-H sulfenylation of imidazoheterocycles using odorless, inexpensive elemental sulfur in DMSO to synthesize sulfur-bridged imidazoheterocycles under metal-free conditions is reported. The amount of...

γ-Hydroxy-γ-butyrolactams as 1,2-bis-electrophiles in a Brønsted/Lewis acid-free synthesis of condensed nitrogen heterocycles

“…It is worth noting that the related one-pot reaction of 2-aminopyridines 9 with arylglyoxals and 1,3-dicarbonyl compounds described previously, 49 but among those presented in the literature, [50][51][52][53] the most common method is based on the reaction with a-halogenketones. [54][55][56][57] A plausible mechanism for the cascade transformation leading to 2-arylquinoxaline 8 is presented in Scheme 8. Under the chosen conditions, 5-hydroxy-3-pyrrolin-2-one 1 forms Nformamide acyliminium cation 5, which undergoes a series of nucleophilic attacks by 1,3-phenylenediamine 6 leading to products 12 and 7, respectively.…”

“…It is worth noting that the related one-pot reaction of 2-aminopyridines 9 with arylglyoxals and 1,3-dicarbonyl compounds described previously, 49 but among those presented in the literature, 50–53 the most common method is based on the reaction with α-halogenketones. 54–57…”

K3PO4‐Promoted Cycloannulation of (E)‐β‐Iodovinyl Sulfones with ortho‐Hydroxy‐Chalcones/Cinnamates for the Synthesis of 2,3,4‐Trisubstituted 4H‐Benzopyran Derivatives

“…), leading to inferior results (entries 8 and 9). We then screened other solvents, such as DMA, DMSO, MeCN, PhCl, and PEG were not beneficial in improving the yield (entries [10][11][12][13][14]. No reaction occurred without a base, thus indicating that the base plays a crucial role in the Scheme 1.…”

“…In continuation of our efforts on organosulfur chemistry [11] and β-iodovinyl sulfones, [12] we assumed that the multifunctional (E)-β-iodovinyl sulfones [13] might have great potential to enrich in delivering 3sulfonyl-4H-benzopyrans via tandem oxa-Michael addition and cyclization process. Previously, we reported Pd-catalyzed cycloannulation between (E)-β-iodovinyl sulfones and 2-halophenols to afford 2,3-disubstituted benzofurans in good to high yields (Scheme 1d).…”

Unified Radical Sulfonylative-Annulation of 1,6-Enynols with Sodium Sulfinates: A Modular Synthesis of 2,3-Disubstituted Benzoheteroles

“…Benzofurans, benzothiophenes, and indoles are widely distributed in bioactive natural products, pharmaceuticals, and functional organic materials (Figure a). , In sharp contrast, sulfones are an indispensable functional group in organic synthesis as well as a blueprint in medicinal and agrochemical chemistry (Figure b). In continuation of our efforts on organosulfur chemistry and cycloannulation strategies, herein, we report a novel and highly efficient AgNO 3 -catalyzed cascade sulfonylative-cyclization of propargylic alcohol-bearing 1,6-enynes with sodium sulfinates to access 2,3-disubstituted benzoheterole derivatives. More interestingly, a three-component reaction is also realized using 1,6-enynols, aryldiazonium salts, and Na 2 S 2 O 5 (as an SO 2 surrogate) to generate similar analogues, which would be an attractive alternative to existing methods.…”