α‐Amino acid derivatives are key components of the molecules of life. The synthesis of α‐amino carbonyl/carboxyl compounds is a contemporary challenge in organic synthesis. Herein, we report a practical method for the preparation of α‐amino acid derivatives via direct hydrative amination of activated alkynes under mild conditions, relying on sulfinamides as the nitrogen source. Computational studies suggest that the reaction is enabled by a new type of sulfonium [2,3]‐sigmatropic rearrangement.

The Schiff base HL [N,N'-ethylenebis(3-methoxysalicylaldimine)] or HL [N,N'-ethylenebis(3-ethoxysalicylaldimine)] was reacted with MCl·xHO and SnCl·5HO to afford the supramolecular heterobimetallic systems (HED)·2[ML]·[SnCl] [M = Cu, L = L (1), L = L (2); M = Ni, L = L (3), L = L (4); ED = 1,2-ethylenediamine], whose structures were established by single crystal X-ray analyses. Each structure includes different entities, viz. a mononuclear [CuL]/[NiL] neutral complex (coformer), a hexachlorostannate dianion [SnCl], a 1,2-ethylenediammonium dication (HED) and, only in 2 and 4, a methanol molecule. Based on the work of Grothe et al. (Cryst. Growth Des., 2016, 16, 3237-3243), compounds 1 and 3 are cocrystal salts, 2 and 4 are cocrystal salt solvates. The ionic pairs (HED)·[SnCl] in 1-4 are encapsulated by the Cu- or Ni-complexes, and stabilized by N-HO and one N-HCl bond interactions leading to infinite 1D chains. The antimicrobial studies of 1-4 against yeasts (C. albicans and S. cerevisiae) and Gram-positive (S. aureus and E. faecalis) and -negative bacteria (P. aeruginosa and E. coli) indicate that the NiSn systems (3 and 4) are more active than the analogous CuSn ones (1 and 2).

A selenium-catalysed para-hydroxylation of N-arylhydroxamic acids is reported. Mechanistically, the reaction comprises an NÀO bond cleavage and consecutive seleniuminduced [2,3]-rearrangement to deliver para-hydroxyaniline derivatives. The mechanism is studied through both 18 Ocrossover experiments as well as quantum chemical calculations. This redox-neutral transformation provides an unconventional synthetic approach to para-aminophenols.

An unusual example of π-acid catalyst-dependent selectivity in the cycloisomerization of alkene-tethered sulfonium ylides affords cyclopropanes or dihydrofurans with excellent control of chemoselectivity.