Practical Synthesis of Tenofovir Alafenamide Fumarate Inspired by New Retrosynthetic Disconnection Featuring a Novel Carbon–Phosphorus Bond Construction Methodology

Tenofovir alafenamide fumarate (TAF) is rising as a mainstay antiretroviral agent for the treatment of HIV and chronic HBV infections. A de novo practical synthesis of TAF circumventing tenofovir (PMPA) has been accomplished on a 7 g scale. This reimagined synthesis of TAF, inspired by a hitherto uncharted retrosynthetic disconnection, centers on the P-alkylation of silylated diphenyl phosphonate 11 (as acceptor) with methylthiomethyl (MTM) ether derivative 12 (as donor) in the presence of NIS/TfOH combination as a promoter to construct the strategic carbon–phosphorus bond. This PMPA-free synthesis of TAF not only removes the intrinsic drawbacks encountered by the PMPA-dependent commercial process but also is beneficial to the diversification of the synthetic portfolio of TAF. Furthermore, this type of P-alkylation reaction with defined stereochemistry could be deployed for the late-stage modification of druglike molecules and natural products to access valuable phosphonate derivatives.