Pentafluoroethylation of unactivated C­(sp2)–X bonds (X = I, Br) using a storable, “ligandless” CuC2F5 reagent prepared by controlled self-condensation of ready available TMSCF3-derived CuCF3 has been developed. A thorough analysis by 19F NMR and ESI-MS revealed the nature of this reagent in solution. The operational simplicity and robustness of this system enables the efficient, late-stage incorporation of C2F5 units into a variety of (hetero)­aryl and complex alkenyl halides such as glycals, nucleosides, and nucleobases.

We herein present a flexible approach for the incorporation of CF units into a predefined site of electron-rich alkenes that exploits the regiocontrolled introduction of an iodine handle and subsequent trifluoromethylation of the C(sp)-I bond using fluoroform-derived "ligandless" CuCF. The broad substrate scope and functional group tolerance together with the scalability and purity of the resulting products enabled the controlled, late-stage synthesis of single regioisomers of complex CF-scaffolds, such as sugars, nucleosides (antivirals), and heterocycles (indoles and chromones), with potential for academic and industrial applications.

A method for the selective activation of thioglycosides that uses the N-thiophilic reagent O-mesitylenesulfonylhydroxylamine (MSH) as a promoter is presented. The reaction proceeds via anomeric mesitylensulfonate intermediates, which could be isolated and fully characterized by placing a fluorine atom at the C2 position. In the presence of a soft Lewis acid, glycosylation reaction proceeds at ambient temperature with good yields. It is further demonstrated that it is possible to orthogonally activate S-ethyl in the presence of S-phenyl donors, enabling the design of sequential glycosylation strategies.

Herein we present a chemical approach for the ready preparation of d-sarmentosyl donors enabling the first total synthesis and structure validation of cardenolide N-1, a challenging 2,6-dideoxy-3-O-methyl-β-d-xylo-hexopyranoside extracted from Nerium oleander twigs that displays anti-inflammatory properties and cell growth inhibitory activity against tumor cells. The strategy highlights the synthetic value of the sequential methodology developed in our group for the synthesis of 2-deoxyglycosides. Key steps include Wittig-Horner olefination of a d-xylofuranose precursor, [I]-induced 6-endo cyclization, and 1,2-trans stereoselective glycosylation.