Thianthrenation-Enabled Pyrrolidin-2-yl and Tetrahydrofuran-2-yl Methylation of (Hetero)Arenes

Abstract

The mild and efficient palladium-catalyzed pyrrolidin-2-yl and tetrahydrofuran-2-yl methylation of (hetero)arenes has been developed. A wide range of (hetero)arenes underwent the regioselective thianthrenation to generate the arylthianthrenium triflate, and the developed Pd-catalyzed alkene carboamination and carboalkoxylation reactions afforded the corresponding biologically important pyrrolidine and tetrahydrofuran derivatives. Mechanistic studies indicated that this reaction proceeds through a syn-heteropalladation mechanistic pathway. The demonstrated late-stage functionalization and enantioselective reaction will help to promote the potential application of the established method in organic synthesis and related fields.

Palladium-Catalyzed Domino Conversion of Aryl–Thianthreniums with Anhydrides: Rapidly Building Highly Functionalized Fluorenones

“…Noteworthily, the generated aryl–thianthreniums (aryl-TTs) as a popular electrophile featured quite high reactivity, as well as the theme that the removed TT fragment could be fully recovered (Scheme b) . Encouraged by this, a plethora of organic variants involving aryl-TTs were successively developed, especially in transition-metal-catalyzed systems because of the easier oxidative addition at the C–S unit . Following this program, a set of functional groups were capable of being in situ installed to produce a diversity of substituted arenes.…”

Synthesis of Tetrahydrofurans and Pyrrolidines by Copper-Catalyzed Oxy/Aminoarylation of Alkenes

“…Intramolecular variants are therefore especially attractive and efficient because, in addition to providing a useful and general entry to a range of (hetero)­cycles, the regioselectivity is in general controlled by the size of the cycle formed. In this perspective, a set of efficient processes have been notably reported over the years for the inter/intramolecular aminoarylation , and oxyarylation ,,,− , of alkenes possessing an internal nitrogen- or oxygen- based nucleophile, respectively. Aryl boronic acids, ,, diazonium salts, ,, silanes, halides, ,,,,,, arylthianthrenium triflates, as well as diaryliodonium salts , could be successfully used as arylating agents, and these reactions were shown to be readily catalyzed mostly by palladium, ,,,,,,, gold, ,,,,,, and copper , complexes.…”