Carbon–Carbon and Carbon–Heteroatom Bond-Forming Transformations Catalyzed by Calcium(II) Triflimide

Abstract

The aim of this short review is to highlight the interest of using Ca(NTf 2) 2 as catalyst in CC and C-X bond-forming reactions. The ability of this complex to activate alcohols, alkenes, ketones, and cyclopropanes towards nucleophilic additions and other chemical processes is shown though a set of selected examples, which illustrate the substrate scope and the synthetic applications offered by this 'green' calcium salt. 1 Introduction 2 Synthetic Applications 3 Conclusion Key words ammonium salt, calcium, CC bond-forming reactions, CO bond functionalization, C-X bond-forming reactions, homogeneous catalysis, weakly coordinating anion After graduating from ESPCI, David Leboeuf (left) pursued his Ph.D. at the University Pierre et Marie Curie (UPMC-Paris 6) with Prof. Max Malacria until 2009 (on Co-, Rh-, and Au-catalyzed cyclizations). After 2.5 years of postdoctoral research at the University of Rochester with Prof. Alison Frontier (on Cu-mediated Nazarov cyclizations) and 1 year at the Institute of Chemical Research of Catalonia (ICIQ) with Prof. Antonio Echavarren (on the development of new Au catalysts), he was appointed by the CNRS as Chargé de Recherche in 2013 at the University Paris-Sud, where he started research program dedicated to calcium catalysis and supramolecular chemistry. Vincent Gandon (right) received his Ph.D. in 2002 from the University of Reims Champagne Ardenne (group of Prof. Jan Szymoniak). After a postdoctoral stay at the University of California, Riverside, in the group of Prof. Guy Bertrand, he joined the faculty of the Pierre et Marie Curie University in Paris in 2003 and worked as Assistant Professor in the laboratory of Prof. Max Malacria. In 2009, he was appointed full Professor at the Paris-Sud University with a research excellence chair. Since 2012, Vincent has been a junior member of the Institut Universitaire de France (IUF), and since 2014, a junior distinguished member of the French Chemical Society (SCF). His research interests are focused on homogeneous catalysis using cobalt, gold, calcium, and gallium complexes, both from an experimental and a theoretical point of view.

Calcium(II)- and Triflimide-Catalyzed Intramolecular Hydroacyloxylation of Unactivated Alkenes in Hexafluoroisopropanol

“…As part of our continuing efforts to expand the reactivity of unactivated alkenes, this reaction piqued our attention. In previous studies, we have demonstrated that the association of a catalytic amount of calcium­(II) salts with hexafluoroisopropanol (HFIP) , was a powerful synthetic tool regarding the hydroamidation of unactivated alkenes and the hydroarylation of highly deactivated styrenes . In these reactions, the role of calcium is not to act as a traditional Lewis acid that will activate either the nucleophile or the olefin but, instead, to strengthen the acidity of H-bond clusters of HFIP and trigger the hydrofunctionalization process .…”

Kudos and Renaissance of s-Block Metal Chemistry

“…Future tasks related to the chemistry of these s-block organometallics include stability and reactivity [17], catalysis and stoichiometric conversions [18,21], Lewis acidity and nucleophilicity [24]. Quantum chemical calculations are valuable tools to elucidate the agostic and π-interactions between the s-block metal ions and multiple bonds [25,26].…”

Calcium-catalyzed reactions of element-H bonds

“…In contrast to the wide applications of limestone being used as the building materials, the use of this element as catalyst has been underexploited for quite a long time. Investigations on Ca catalysis are just unfolding in the past decade and a series of interesting reactions have been reported [11][12][13][14][15][16]. Recently, during our ongoing investigations on green catalysis [17][18][19][20][21][22], it was unexpectedly found that the Ca(OH) 2 possessed superior catalytic activities over the conventionally used NaOH or KOH catalysts and these interesting results shifted our attention to the subject of Ca catalysis [20][21][22].…”