The synthesis of vinyl sulfone derivativesviathe reaction of arylpropiolic acids, K2S2O5, and aryl boronic acids is reported. The CuBr2/1,10-phenanthroline catalytic system in the presence of acetic acid provide
An, Seunghwan,Lee, Sunwoo,Song, Kwang Ho
supporting information
p. 7827 - 7831
(2021/09/28)
Intermolecular [2 + 2] Photocycloaddition of α,β-Unsaturated Sulfones: Catalyst-Free Reaction and Catalytic Variants
2-Aryl-1-sulfonyl-substituted cyclobutanes were prepared in an intermolecular [2 + 2] photocycloaddition from various α,β-unsaturated sulfones and olefins upon irradiation at λ = 300 nm (26 examples, 60-99% yield). Lewis acids catalyzed the [2 + 2] photocycloaddition of 2-benzimidazolyl styryl sulfones. At short wavelengths, the latter substrates underwent C-S bond cleavage but AlBr3 (5 mol %) allowed for an intermolecular reaction with 2,3-dimethyl-2-butene at longer wavelengths. A chiral-at-metal Lewis acid (2 mol %) facilitated an enantioselective reaction (up to 77% ee).
Jeremias, Noah,Mohr, Lisa-Marie,Bach, Thorsten
supporting information
p. 5674 - 5678
(2021/08/03)
Visible-Light-Mediated Alkenylation of Alkyl Boronic Acids without an External Lewis Base as an Activator
Herein we report a protocol for the direct visible-light-mediated alkenylation of alkyl boronic acids at room temperature without an external Lewis base as an activator, and we propose a mechanism involving benzenesulfinate activation of the alkyl boronic acids. The protocol permits the efficient functionalization of a broad range of cyclic and acyclic primary and secondary alkyl boronic acids with various alkenyl sulfones. We demonstrated its utility by preparing or functionalizing several pharmaceuticals and natural products.