A convenient hydroiodination of alkynes using I2/PPh3/H2O and its application to the one-pot synthesis of trisubstituted alkenes via iodoalkenes using Pd-catalyzed cross-coupling reactions

Hydroiodination‐Triggered Cascade Reaction with I2/PPh3/H2O: Metal‐Free Access to 3‐Substituted Phthalides from 2‐Alkynylbenzoates

“…The proposed reaction pathway for the synthesis of 3‐substituted phthalides 2 from methyl 2‐[(trimethylsilyl)ethynyl]benzoates 1 through a hydroiodination‐triggered cascade reaction is shown in Scheme . As previously reported,, I 2 , PPh 3 , and H 2 O quantitatively give HI and [Ph 3 POH] + [I] – . The generated species can cause the hydroiodination of alkynes.…”

“…Synthetic methods involving cascade reactions have garnered considerable attention, because multiple purification steps are avoided, and they produce less waste and require less time. Our group recently reported that the hydroiodination of alkynes with I 2 , PPh 3 , and H 2 O afforded iodoalkenes . Furthermore, the hydroiodination was successfully applied to a one‐pot Pd‐catalyzed cross‐coupling reaction; notably, the hydroiodination residues did not prevent the subsequent cross‐coupling reactions .…”

“…Our group recently reported that the hydroiodination of alkynes with I 2 , PPh 3 , and H 2 O afforded iodoalkenes . Furthermore, the hydroiodination was successfully applied to a one‐pot Pd‐catalyzed cross‐coupling reaction; notably, the hydroiodination residues did not prevent the subsequent cross‐coupling reactions . Upon investigating the hydroiodination of various alkynes, methyl 2‐[(trimethylsilyl)ethynyl]benzoate ( 1a ) gave 3‐methylphthalide ( 2a ) [Equation (2)].…”

Metal‐Free Synthesis of β‐Bromoalkenyl Sulfides via Deoxygenative Bromination/Olefination/Sulfenylation of Ketones with Sulfonyl Hydrazides and Pyridinium Tribromide

“…[16] Under argon atmosphere, to a solution of E-3a (70.45 mg, 0.20 mmol) in anhydrous CH 3 CN (1.0 mL) was added 4-methylphenylacetylene (27.88 mg, 0.24 mmol), Et 3 N (40.48 mg, 0.40 mmol), CuI (1.90 mg, 0.01 mmol) and Pd(PPh 3 ) 4 (11.56 mg, 0.01 mmol). [16] Under argon atmosphere, to a solution of E-3a (70.45 mg, 0.20 mmol) in anhydrous CH 3 CN (1.0 mL) was added 4-methylphenylacetylene (27.88 mg, 0.24 mmol), Et 3 N (40.48 mg, 0.40 mmol), CuI (1.90 mg, 0.01 mmol) and Pd(PPh 3 ) 4 (11.56 mg, 0.01 mmol).…”

“…Upon treatment with m-CPBA, E-3a successfully converted into the corresponding oxidized products E-13a in a yield of 87%. [16] Furthermore, introducing trimethylsilylacetylene to E-3a could also take place catalyzed by palladium, providing conjugated enyne E-13d in 80% yield. E-3a via a Suzuki-Miyaura coupling furnished E-13b in an excellent yield (89%), [15] while E-13c was generated via Sonogashira-Hagihara coupling in a yield of 90%.…”