Enantioselective electrophilic fluorination of α-aryl-tetralones using a preparation of N-fluoroammonium salts of cinchonine

Abstract

The enantioselective electrophilic fluorination of α-aryl-tetralones is promoted by cinchonine/selectfluor combinations. This strategy allows a facile synthesis of the corresponding 2-fluoro-2-aryl-1-tetralones with excellent yields (up to >98%) and moderate to good enantioselectivity (up to74%).

N‐Fluoro Ammonium Salts of Cinchona Alkaloids in Enantioselective Electrophilic Fluorination

“…Costa and co‐workers in 2019 using an ex situ prepared acetonitrile solution of cinchonine and Selectfluor (Scheme 22). [57] This way, a good number of fluorotetralones were obtained in up to 74 % ee. Other Cinchona alkaloids were evaluated but were less efficient; surprisingly (DHQD) 2 PHAL gave no reaction.…”

Oxidation: C–X Bond Formation (X = Halogen, S, Se)

“…This strategy was used in the enantioselective fluorination of -aryl-tetralones via a combination of a cinchona alkaloid and Selectfluor (Scheme 1). 1 The results are very sensitive to the structure of the alkaloid, the decoration of the substrate and to the reaction temperature. In particular, the enantioselectivity showed a strong dependence of the -aryl substituent (-alkyl ketones were not studied).…”

Vibrational Circular Dichroism for the Assignment of Absolute Configuration of Natural Products in Brazil

“…In this section, we will present a list of natural products and related compounds studied by Brazilian researchers (Table S1), which had their absolute configuration assigned using VCD spectroscopy and DFT calculations, associated or not with other techniques (Batista Jr et al 2011b;2013;2015b;Batista et al 2019;Caldas et al 2020;Caleffi et al 2019;Canzi et al 2018;Covington et al 2016;Demarque and Merten 2017;Felippe et al 2012;Gimenes et al 2019;Joseph-Nathan et al 2010;Lianza et al 2020;Londero et al 2021;Medina et al 2019;Morais et al 2020;Ortega et al 2017;Ortega et al 2018;Ortega et al 2019;Queiroz et al 2019;Rodriguez et al 2020;Santos Jr et al 2014;Scatena et al 2017;Socolsky et al 2012;Souza et al 2019;Teodoro et al, 2018a;2018b). Some selected examples will be discussed in detail below.…”