Gold-catalyzed reactions have witnessed an exponential growth in the past decade. When the unique modes of activation exhibited by gold species meet species with either fluorinated building blocks or fluorinating reagents, new opportunities arise for the development of new methodologies in fluoroorganic chemistry. Indeed, gold and fluorine truly formed a very fruitful partnership, and different types of reactivity emerged from their combination. This review gives an overview of such endeavors. The special properties imparted by fluorine to organic molecules have been exploited in gold-catalyzed processes, allowing for the generation of unprecedented fluorinated chemical entities. Thus, the interaction of gold salts with fluorinated building blocks has been revised. In a second section, recent developments in gold-catalyzed nucleophilic fluorinations have been covered. The development of new gold catalysts that stabilize the Au-F bond as well as recent mechanistic studies in the field raised the interest of these types of methodologies for the generation of new C-F bonds. The use of electrophilic fluorine sources enabled new modes of gold catalysis. The incorporation of Selectfluor as an external oxidant constituted a new paradigm in gold chemistry, incorporating the elusive Au(I)/Au(III) redox couple in gold-catalyzed transformations. This strategy provided access to both new fluorinated chemical entities and nonfluorinated derivatives by means of coupling reactions. Those topics have been reviewed in the last two sections.
A palladium-catalyzed three-component coupling of α-olefins, aryldiazonium salts, and bis-(pinacolato)diboron affords direct access to chiral benzylic boronic esters. This process is rendered highly enantioselective using an unprecedented example of cooperative chiral anion phase transfer and transition-metal catalysis.
Herein we report the first highly enantioselective allenoate-Claisen rearrangement using doubly axially chiral phosphate sodium salts as catalysts. This synthetic method provides access to β-amino acid derivatives with vicinal stereocenters in up to 95% ee. We also investigated the mechanism of enantioinduction by transition state (TS) computations with DFT as well as statistical modeling of the relationship between selectivity and the molecular features of both the catalyst and substrate. The mutual interactions of charge-separated regions in both the zwitterionic intermediate generated by reaction of an amine to the allenoate and the Na +salt of the chiral phosphate leads to an orientation of the TS in the catalytic pocket that maximizes favorable noncovalent interactions. Crucial arene−arene interactions at the periphery of the catalyst lead to a differentiation of the TS diastereomers. These interactions were interrogated using DFT calculations and validated through statistical modeling of parameters describing noncovalent interactions.
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