(2-Fluoroallyl)pyridinium tetrafluoroborates: novel fluorinated electrophiles for Pd-catalyzed allylic substitution

Abstract

An efficient two-step approach to 2-fluoroallyl amines was developed that involves the synthesis of (2-fluoroallyl)pyridinium tetrafluoroborates from readily available gem-bromofluorocyclopropanes and the application of the former as novel and stable...

Boronyl Borinic Esters: Preparation as B2pin2/secBuLi/TFAA Adducts, Structural Insights and Reactivity in Pd‐catalyzed Allylic Borylation

“…In our recent studies on the development of new synthetic approaches to biologically relevant fluoroalkenes, [9,10] we encountered the task of borylation of (2‐fluoroallyl)pyridinium salts that was found to be challenging. These pyridinium salts are sensitive even to weak bases like alkali carbonates or tertiary amines and decompose with fluorine elimination [9a] . Therefore, no alkoxides could be applied for B 2 pin 2 activation in this case and the development of a base‐free activation strategy was required.…”

Cobalt-Catalyzed Fluoroallyllation of Carbonyls via C–C Activation of gem-Difluorocyclopropanes

“…Although the catalytic synthesis of homoallylic alcohols via transition-metal-catalyzed allylation has been well-studied, the general access to fluorinated homoallylic alcohols still remains underdeveloped. Recently, elegant works on the enantioselective iridium-catalyzed terminal (2-fluoro)-allylation of primary alcohols and successive Cu- and Pd-catalyzed branched fluoroallylation through a 1-chloro-1-fluorocyclopropane transformation were achieved (Scheme a). However, compared to the well-established transition-metal-catalyzed allylation of carbonyls, the catalytic formation of linear fluorinated homoallylic alcohols still lags far behind.…”