An efficient Ag/pyridine co-mediated oxidative arylthiocyanation of activated alkenes via radical addition/cyclization cascade process was developed. This reaction could be carried out under mild conditions to provide biologically interesting 3-alkylthiocyanato-2-oxindoles in good to excellent yields. Mechanistic studies suggested a unique NCS• radical addition path and clarified the dual roles of catalytic pyridine as base and crucial ligand to accelerate the oxidation of Ag(I) to Ag(II), which is likely oxidant responsible for the formation of NCS• radical. These mechanistic results may impact the design and refinement of other radical based reactions proceeding through catalytic oxidations mediated by Ag(I)-pyridine/persulfate. The chemical versatility of thiocyanate moiety was also highlighted via SCN-tailoring chemistry in post-synthetic transformation for new S-C(sp3/sp2/sp), S-P, and S-S bonds constructions. The protocol provides an easy access to many important bioisosteres in medicinal chemistry and an array of sulfur-containing 2-oxindoles that are difficult to prepare by other approaches.

No abstract

An efficient aza‐Michael addition of (R or S)‐α‐phenethylamine, a chiral nitrogen nucleophile to (E)‐nitroalkenes 2 a‐f permits the synthesis of vicinal diamines (or 1, 2‐di‐amine) after reduction of the 1, 4‐adducts 3 a‐f (or 3’a‐f). The key adducts 3 a‐f (or 3’a‐f) can be obtained in good yields (up to 78%) and excellent diastereoselectivities (up to > 98:2 dr (diastereomeric excess ratio)). In addition, this is one of the scarce examples where chiral phenethylamine and nitroalkenes have been used in catalyst‐free aza‐Michael additions. Our developed strategy opens an efficient entry to synthetic building blocks of vicinal diamines for natural products and drugs.