N‐Iodosuccinimide as Bifunctional Reagent in (E)‐Selective C(sp²)−H Sulfonylation of Styrenes

Abstract

Herein we report the use of N-iodosuccinimide (NIS) as a bifunctional reagent for a regio-and (E)-selective C (sp 2 )-H sulfonylation reaction of styrenes. Styrenes and sulfonyl hydrazides treated with NIS and potassium carbonate in ethanol at 70°C resulted in (E)-vinyl sulfones exclusively with good to excellent yields. NIS, plays a dual role to generate sulfonyl radical from sulfonyl hydrazides at an initial stage and finally gives β-iodosulfone intermediate which was further converted to (E)-vinyl sulfones. Overall, a sustainable method for mild, metal free, convenient, one pot and direct synthesis of (E)-vinyl sulfones from styrenes are demonstrated via a CÀ S coupling reaction. Scheme 1. The present work: a) Direct synthesis of (E)-vinyl sulfone from styrenes using N-iodosuccinimide as b) The small molecule system chemistry approach via bifunctionality of NIS. . (E)-1-Methyl-4-((4-(trifluoromethyl)styryl)sulfonyl)benzene (3 ja): [22b] R f = 0.4 (20% ethyl acetate in hexane); white solid; yield 96% (128 mg); mp 120-124°C (lit. [22b] 120-122°C); 1 H NMR (400 MHz, CDCl 3 ) δ 7.83 (d, J = 8.2 Hz, 2H),7.67 (d, J = 15.4 Hz, 1H), 7.64 (d, J = 8.2 Hz, 2H), 7.58 (d, J = 8.2 Hz, 2H), 7.36 (d, J = 8.2 Hz, 2H), 6.94 (d, J = 15.4 Hz, 1H), 2.44 (s, 3H); 13 C NMR (175 MHz, CDCl 3 ) δ 145.0, 140.0, 137.3, 136.0, 132.7 (q, 2 (E)-4-(2-Tosylvinyl)benzonitrile (3 ka): [22b] R f = 0.4 (20% ethyl acetate in hexane); white solid; yield 91% (120 mg); mp 125-128°C (lit. [22b] 125-127°C); 1 H NMR (400 MHz, CDCl 3 ) δ 7.83 (d, J = 8.2 Hz, 2H), 7.68 (d, J = 8.4 Hz, 2H), 7.64 (d, J = 15.4 Hz, 1H), 7.56 (d, J = 8.4 Hz, 2H), 7.37 (d, J = 8.2 Hz, 2H), 6.95 (d, J = 15.4 Hz, 1H), 2.45 (s, (E)-1-Methyl-4-((4-nitrostyryl)sulfonyl)benzene (3 la): [28c] R f = 0.45 (20% ethyl acetate in hexane); white solid; yield 84% (103 mg); mp 172-174°C (lit. [28c] 172-175°C); 1 H NMR (700 MHz, CDCl 3 ) δ 8.24 (d, J = 8.8 Hz, 2H), 7.84 (d, J = 8.2 Hz, 2H), 7.69 (d, J = 15.4 Hz, 1H), 7.63 (d, J = 8.8 Hz, 2H), 7.38 (d, J = 8.2 Hz, 2H), 6.99 (d, J = 15.4 Hz, 1H), 2.45 (s, 3H); 13 (E)-1-Methyl-4-((4-nitrostyryl)sulfonyl)benzene (3 la): [28c] R f = 0.45 (20% ethyl acetate in hexane); white solid; yield 84% (103 mg); mp 172-174°C (lit. [28c] 172-175°C); 1 H NMR (700 MHz, CDCl 3 ) δ 8.24 (d, J = 8.8 Hz, 2H), 7.84 (d, J = 8.2 Hz, 2H), 7.69 (d, J = 15.4 Hz, 1H), 7.63 (d, J = 8.8 Hz, 2H), 7.38 (d, J = 8.2 Hz, 2H), 6.99 (d, J = 15.4 Hz, 1H), 2.45 (s, 3H); 13

Sulfonyl Hydrazides in Organic Synthesis: A Review of Recent Studies

“…Radical Heck‐type reactions of terminal alkenes with sulfonyl hydrazides have emerged as a straightforward access to vinyl sulfones (Eq. 6‐1).…”

“…6‐1). The [I] system, such as TBAI/TBHP, KI/TBHP, NIS, KI/electrosynthesis, I 2 /TBHP were all effective to act as the radical initiator. The sulfonylation proceeded via the sequence of addition and elimination of HI.…”

“…The sulfonylation proceeded via the sequence of addition and elimination of HI. Both styrenes and butyl acrylate could give good yields, while aliphatic alkenes failed to yield the desired product. As the temperature increased (110 °C), the radical Heck of aliphatic alkene (R= t Bu) was obviously improved, which indicated a lower temperature were good for the stability of β ‐iodo sulfone intermediates (Scheme ).…”

I2/DMSO-Catalyzed Transformation of N-tosylhydrazones to 1,2,3-thiadiazoles

“…The reaction proceeded uneventfully in the presence of 2,6-di-tert-butyl-4-methylphenol (BHT). In the absence of sulfur, decomposition of 1a occurred, providing II ′ as the main product (Pramanik et al, 2019). In this case, the isolated II ′ is not pure, and the 1 H and 13 C NMR spectra led us to have speculation on the formation of II.…”

Recent Progress in Sulfonylation via Radical Reaction with Sodium Sulfinates, Sulfinic Acids, Sulfonyl Chlorides or Sulfonyl Hydrazides

“…In the same year, the N-iodosuccinimide (NIS) mediated sulfonylation of styrenes in ethanol was reported by Mal group. [105] Both the generation of sulfonyl radical from sulfonyl hydrazides at an initial stage and the formation of β-iodosulfone intermediate were needed the assistance of NIS. Different from Wei's work, HI elimination was proposed to form the desired products (Scheme 91).…”