The development of practical methods for the direct and selective C(sp^(3))‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry.Although the radical‐mediated hydrogen atom transfer(HAT)p...The development of practical methods for the direct and selective C(sp^(3))‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry.Although the radical‐mediated hydrogen atom transfer(HAT)process has shown considerable potential in such reactions,it still faces fundamental problems associated with reactivity and selectivity.Herein,we report a convenient and economic approach to site‐selective C(sp^(3))‒H sulfonylation via photo‐induced HAT catalysis.Employing a conjugated polycyclic quinone as a direct HAT photocatalyst,commercially available inorganic sulfinates as the sulfonylation source,copper triflate as an inexpensive oxidant,a variety of toluene derivatives and cycloalkanes were converted into biologically and synthetically interesting sulfone products under mild conditions.The mechanistic studies reveal that the reaction sequence involves direct HAT‐induced radical formation and a subsequent copper‐mediated organometallic process for the C‒S bond formation.This method offers an appealing opportunity to furnish high value‐added products from abundant hydrocarbon starting materials and inexpensive reagents.展开更多
Titanium complexes derived from 2,4-di-tert-butyl-6-（（2-（arylsulfinyl）phenylimino）methyl）phenol are designed and synthe- sized. X-ray diffraction studies reveal that the complexes adopt distorted octahedral geom...Titanium complexes derived from 2,4-di-tert-butyl-6-（（2-（arylsulfinyl）phenylimino）methyl）phenol are designed and synthe- sized. X-ray diffraction studies reveal that the complexes adopt distorted octahedral geometry with O（phenol）, N（imine）, and O（sulfoxide） coordinated with titanium. Combined with modified methylaluminoxane（MMAO）, the complexes exhibit moderate to high activity to afford polyethylene even at 120 ℃ under 1 atm ethylene pressure. The complexes also show excellent capability in copolymerization of ethylene with either 1-hexene or norbornene. Results indicate that the introduction of sulfoxide groups could open the space around central metal and favors the insertion of bulky comonomers.展开更多
文摘The development of practical methods for the direct and selective C(sp^(3))‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry.Although the radical‐mediated hydrogen atom transfer(HAT)process has shown considerable potential in such reactions,it still faces fundamental problems associated with reactivity and selectivity.Herein,we report a convenient and economic approach to site‐selective C(sp^(3))‒H sulfonylation via photo‐induced HAT catalysis.Employing a conjugated polycyclic quinone as a direct HAT photocatalyst,commercially available inorganic sulfinates as the sulfonylation source,copper triflate as an inexpensive oxidant,a variety of toluene derivatives and cycloalkanes were converted into biologically and synthetically interesting sulfone products under mild conditions.The mechanistic studies reveal that the reaction sequence involves direct HAT‐induced radical formation and a subsequent copper‐mediated organometallic process for the C‒S bond formation.This method offers an appealing opportunity to furnish high value‐added products from abundant hydrocarbon starting materials and inexpensive reagents.
基金supported by the National Natural Sciences Foundation of China (21174159, 21121062)the Science and Technology Commission of Shanghai Municipalitythe Chinese Academy of Sciences
文摘Titanium complexes derived from 2,4-di-tert-butyl-6-（（2-（arylsulfinyl）phenylimino）methyl）phenol are designed and synthe- sized. X-ray diffraction studies reveal that the complexes adopt distorted octahedral geometry with O（phenol）, N（imine）, and O（sulfoxide） coordinated with titanium. Combined with modified methylaluminoxane（MMAO）, the complexes exhibit moderate to high activity to afford polyethylene even at 120 ℃ under 1 atm ethylene pressure. The complexes also show excellent capability in copolymerization of ethylene with either 1-hexene or norbornene. Results indicate that the introduction of sulfoxide groups could open the space around central metal and favors the insertion of bulky comonomers.
