Photochemical Monoalkylation of Propanedinitrile by Electron-Rich Alkenes

Abstract

The synthesis of monoalkylated propanedinitriles was achieved upon photoirradiation of MeCN/H(2)O solutions containing propanedinitrile (1; malononitrile) and electron-rich alkenes in the presence of lithium carbonate and a catalytic amount of 9-cyanophenanthrene or redox-type photosensitizers (electron-mediating photosensitizers), through regioselective anti-Markovnikov photochemical polar addition of 1 into electron-rich alkenes. With 2,5-dimethyl-2,4-hexadiene (2g) as an electron-rich alkene, propanedinitrile-incorporated dimer 4g was obtained.

One‐Pot, Selective Hydroformylation, Condensation, and Hydrogenation Processes by a Sol–Gel Entrapped Rhodium Complex, an Immobilized Base, and an Ionic Liquid

“…The reaction of a mixture of 1 mmol styrene (1, R 1 = H), 1 mmol propanedinitrile (malononitrile, 3, R 1 = H, R 2 = R 3 = CN), 20.7 bar H 2 , and 20.7 bar CO in the presence of 2.04 ϫ 10 -2 mmol [Rh(cod)Cl] 2 co-entrapped with 4.01 ϫ 10 -2 mmol sodium 3-(diphenylphosphanyl)benzenesulfonate, ionic liquid confined silica sol-gel (vide infra), [4] and 10 mL of each of THF and 1,2-dichloroethane afforded, after 14 h at 80°C, a mixture of 86 % (2-phenylpropyl)propanedinitrile (5, R 1 = H, R 2 = R 3 = CN), [5] 7 % (2phenylpropylidene)propanedinitrile (4, R 1 = H, R 2 = R 3 = CN), [6] 2 % (3-phenylpropylidene)propanedinitrile (8), [7] and traces (Ͻ0.1 %) of its precursor 7. [8] The latter two products result from the linear aldehyde 6 formed in small quantities during hydroformylation.…”

“…(3-Chloropropyl)trimethoxysilane and tetramethoxysilane were obtained from Gelest Silanes and Silicons. Di-µ-chlorobis[(1,2,5,6-η)-1,5-cyclooctadiene]dirhodium, [16] 1-butyl-3-[3-(trimethoxysilyl)propyl]imidazolium chloride, [4] sodium 3-(diphenylphosphanyl)benzenesulfonate, [17] (2-phenylpropylidene)propanedinitrile, [6] (3-phenylpropylidene)propanedinitrile, [7] (2-phenylpropyl)propanedinitrile, [5] (3phenylpropyl)propanedinitrile, [7] and ethyl α-cyano-γ-methylbenzene butanoate [18] were prepared according to literature procedures. The immobilization of the catalyst was performed essentially as described previously.…”

“…[5] Likewise, 1 (R 1 = H) and 3 (R 2 = CN, R 3 = CO 2 C 2 H 5 ) gave up to 180 mg (78 %) ethyl 2-cyano-(2-phenylpropyl)acetate [5, R 1 = H, R 2 = CN, R 3 = (O 2 C 2 H 5 )]. [18] [2-(4-Chlorophenylpropyl)]propanedinitrile (5, R 1 = H, R 2 = R 3 = CN) was obtained in 87-94 % yield as a pale yellow viscous oil.…”

Photoinduced Addition Reactions in Aqueous Media

“…SET from Phen or 43 to 1 44* can also take place. This tandem three-component reaction not only broadens the synthetic usability of the photochemical -monoalkylation method of 42 that we have reported [45], but also enables us to accomplish photoinduced cross coupling under mild and safe conditions such as ambient temperature and in the presence of water and weak base, employing a cyano group as a leaving group. An alternative pathway might involve SET from the anion of 42 to Phen •+ , followed by coupling of the resulting radical with 43 to form A• (path II, Scheme 6.3).…”

Intermolecular Addition Reactions onto CC Multiple Bonds

“…In this case, excited 9-cyanophenanthrene (9-CP) oxidizes an olefin by PET, and the resultant radical cation adds to the malononitrile anion. The resulting radical is then reduced by 9-CP .À and protonated to afford the end products [29]. This represents one of the rare examples involving the photoaddition of a carbanion to an olefin, and is explained by the PET-induced Umpolung of the latter, which thus becomes electrophilic.…”