Iron-catalyzed regioselective synthesis of (E)-vinyl sulfones mediated by unprotected hydroxylamines

Abstract

An Fe-catalyzed unprotected hydroxylamine mediated Heck-type coupling between sulfinic acids and alkenes furnished structurally important (E)-vinyl sulfones with moderate to good yields, high atom-economy and regioselectivity.

Copper-catalyzed 4-HO-TEMPOH mediated phosphorylation of alkenes

“…Based on the above experimental results and previous reports, 9,10 we proposed a plausible mechanism for the phosphorylation of alkenes (Fig. 1).…”

“…More recently, our group demonstrated that an O -unprotected hydroxylamine could act as a mild oxidant and an in situ base, which effectively promoted the sulfonylation of alkenes for regioselective synthesis of ( E )-vinyl sulfones (Scheme 1b). 9 As an extension of this chemistry, we anticipated that the O -unprotected hydroxylamine, 4-HO-TEMPOH (2,2,6,6-tetramethylpiperidine-1,4-diol), might convert H-phosphine oxides into phosphinoyl radicals, which would then undergo a radical addition/single electron transfer (SET)/proton elimination sequence to give structurally diverse alkenylphosphine oxides (Scheme 1c).…”

Photoredox-Catalyzed Radical–Radical Cross-Coupling of Sulfonyl Chlorides with Trifluoroborate Salts

“…Eluent: (petroleum ether/ ethyl acetate = 7/1). 1 45 The title compound was prepared according to the general procedure and purified by flash column chromatography on silica gel to give a white solid, 53.0 mg, 68% yield. E/Z = 2:1.…”

Nickel-Catalyzed Suzuki–Miyaura Coupling in Water for the Synthesis of 2-Aryl Allyl Phosphonates and Sulfones

“…The straightforward method for the preparation of 2-aryl allyl sulfones involves the oxidation of allylic sulfides 13 and the reaction of α-bromomethylstyrenes with arylsulfinates. 14 Sulfonyl radical generated from sulfinic acids, 15 sulfonyl hydrazides catalyzed by Cu under an O 2 atmosphere, 16 FeCl 3 , 17 or tetrabutylammonium iodide (TBAI), 18 and sodium arylsulfinates catalyzed by I 2 19 in the presence of stoichiometric amounts of peroxide have been effectively developed. p -Toluenesulfonylmethyl isocyanide (TosMIC) has been used as a sulfonylating agent in the presence of catalytic amounts of I 2 , 20 Cu, 21 or Co(salen) 2 22 for the formation of 2-aryl allyl sulfones.…”