[ASAP] Catalyst Activation, Chemoselectivity, and Reaction Rate Controlled by the Counterion in the Cu(I)-Catalyzed Cycloaddition between Azide and Terminal or 1-Iodoalkynes
Difluoro(phenylsulfanyl)methane (PhSCF2H) was found to undergo a reaction with aromatic compounds mediated by SnCl4, through a thionium intermediate characterized by NMR and TD-DFT analyses, leading to the formation of a mixture of S,S′-diphenyl dithioacetal and aromatic aldehyde which, after oxidative hydrolysis, provides the aromatic aldehyde in good to excellent yields. The salient feature of the present work is the reaction of activated aromatic compounds containing a deactivating ester functional group, leading to the formylated products in good yields.
© Georg Thieme Verlag Stuttgart · New York
Frontispiece: Enantioselective Brønsted Acid Catalysis as a Tool for the Synthesis of Natural Products and Pharmaceuticals
Chiral Brønsted acids are capable of promoting plenty of enantioselective transformations. From simple substrates, chiral protons build complex enantioenriched scaffolds that are subsequently involved in the total synthesis of bioactive moieties. This review aims to describe the value of such asymmetric catalysis to the synthesis of natural products and pharmaceuticals. The target structures, and the potential disconnections are particularly emphasized. For more information see the Minireview by G. Masson and co-workers on page 3925 ff.
Catalytic Enantioselective Transformations Involving C–H Bond Cleavage by Transition-Metal Complexes