Generation of 1,2-oxathiolium ions from (arysulfonyl)- and (arylsulfinyl)allenes in Brønsted acids. NMR and DFT study of these cations and their reactions

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov,
• Olesya V. Khoroshilova and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2018, 14, 2897–2906, doi:10.3762/bjoc.14.268

• , D2SO4), (arysulfonyl)allenes (ArSO2–CR1=C=CR2R3) and (arylsulfinyl)allenes (ArSO–CR1=C=CR2R3) undergo cyclization into the corresponding stable 1,2-oxathiolium ions, which were studied by means of NMR and DFT calculations. Quenching of solutions of these cations with low nucleophilic media, aqueous HCl

• mixtures, (arylsulfinyl)allenes give allyl alcohols (ArSO2–CR1=CH–C(OH)R2R3). Plausible reaction mechanisms have been proposed for all studied reactions. Keywords: (arylsulfinyl)allenes; (arylsulfonyl)allenes; butadienes; 1,2-oxathiolium ions; thiochromene 1,1-dioxides; Introduction Allenes are widely

• to alcohols 7a,b. Conclusion Transformations of (arylsulfonyl)- and (arylsulfinyl)allenes under the action of the Brønsted superacid TfOH, or strong Lewis acids AlX3 (X = Cl, Br) have been studied. Under electrophilic conditions, these allenes form the corresponding 1,2-oxathiolium ions, which have