Ring-Opening 1,3-Sulfonylation-Fluorination of Donor–Acceptor Cyclopropanes: Three-Component Access to γ-Fluorosulfones

Abstract

A general method for 1,3-bisfunctionalization of donor−acceptor (D−A) cyclopropanes using sulfinate salts and electrophilic fluorination reagents is described. Utilizing Lewis acid catalysis, nucleophilic ring-opening by the sulfinate anion followed by trapping of electrophilic fluorine by the anionic intermediate leads to the formation of γ-fluorosulfones. To the best of our knowledge, this is the first direct one-step synthesis of sulfones fluorinated in the γ-position from a carbon backbone. A mechanistic proposal is presented based on experimental evidence.

Lewis acid-catalyzed one-pot thioalkenylation of donor–acceptor cyclopropanes using in situ generated dithiocarbamates and propiolates

“…8 More recently, the Werz group also demonstrated 1,3-sulfonylation–fluorination using sulfinate salts as nucleophiles (eqn (2)). 9 Considering the scarce existing literature on sulfur-based nucleophilic triggers to open D–A cyclopropanes, we conceived a one-pot thioalkenylation method for D–A cyclopropanes (eqn (3)). This method involves the in situ generation of dithiocarbamates (from amines and CS 2 ) as nucleophilic triggers and the use of alkyl propiolates as electrophiles.…”

Regioselective C3–H Alkylation of Imidazopyridines with Donor–Acceptor Cyclopropanes

“…The strain energy in cyclopropane is stated to be 115 kJ/mol and this energy drives ring-opening and cycloaddition processes . The push-pull mechanism of DA-cyclopropanes, which are usually referred to as 1,3-dipolar zwitterionic synthons, makes them one of the most sought after building blocks for a number of reactions, including ring-opening events, cycloadditions, and rearrangement procedures. − …”