6244-46-8Relevant academic research and scientific papers
Sulfonylative and Azidosulfonylative Cyclizations by Visible-Light-Photosensitization of Sulfonyl Azides in THF
Zhu, Shaoqun,Pathigoolla, Atchutarao,Lowe, Grace,Walsh, Darren A.,Cooper, Mick,Lewis, William,Lam, Hon Wai
supporting information, p. 17598 - 17604 (2017/11/22)
The generation of sulfonyl radicals from sulfonyl azides using visible light and a photoactive iridium complex in THF is described. This process was used to promote sulfonylative and azidosulfonylative cyclizations of enynes to give several classes of highly functionalized heterocycles. The use of THF as the solvent is critical for successful reactions. The proposed mechanism of radical initiation involves the photosensitized formation of a triplet sulfonyl nitrene, which abstracts a hydrogen atom from THF to give a tetrahydrofuran-2-yl radical, which then reacts with the sulfonyl azide to generate the sulfonyl radical.
Stereochemical Aspects in the Insertion by Alkylidenemethylene Carbenoids into the α-C-H Bond of Alkoxides
Oku, Akira,Harada, Toshiro,Hattori, Kazuhiro,Nozaki, Yohko,Yamaura, Yasunari
, p. 3089 - 3098 (2007/10/02)
Primary alkoxides (R1CH2OM; M=K or Li) when treated with haloalkenes (R3R4C=CXY; X=Cl or Br, Y=H or Cl) in the presence of n-BuLi in THF at 0 deg C gave allylic alcohols (R1CH(OH)CH=CR3R4) through the insertion reaction of the corresponding alkylidenemethylene carbenoid () into the α-C-H bond of alkoxides.Secondary alkoxides (R1R2CHOM), under similar reaction conditions, gave butyl adducts (R1R2C(OH)C4H9) in addition to the insertion products.In particular, the C-H insertion of menthyl oxide proceeded without stereospecificity to give a mixture of the axial and equatorial insertion products.These results provided evidence for the hydride abstraction-recombination mechanism in the carbenoid insertion reaction.The regioselective, nonstereospecific insertion reaction was also observed when alkoxides were treated with separately prepared ((2,3-benzo-2-cyclohexylidene)chloromethyl)lithium at temperatures from -95 to -40 deg C.The absence of H-D scrambling in crossover experiments under these reaction conditions clearly showed that the hydride abstraction-recombination mechanism proceeded within a solvent cage.An inversion of configuration on the carbenoid carbon in the hydride abstraction step was proposed on the basis of the E/Z stereoselectivity in the insertion products.
