Late-Stage C(<i>sp</i><sup><i>3</i></sup>)–H Methylation of Drug Molecules
Edna Mao, David W. C. MacMillan
Abstract
Methyl groups are well understood to play a critical role in pharmaceutical molecules, especially those bearing saturated heterocyclic cores. Accordingly, methods that install methyl groups onto complex molecules are highly coveted. Late-stage C–H functionalization is a particularly attractive approach, allowing chemists to bypass lengthy syntheses and facilitating the expedited synthesis of drug analogues. Herein, we disclose the direct introduction of methyl groups via C( sp 3 )–H functionalization of a broad array of saturated heterocycles, enabled by the merger of decatungstate photocatalysis and a unique nickel-mediated S H 2 bond formation. To further demonstrate its synthetic utility as a tool for late-stage functionalization, this method was applied to a range of drug molecules en route to an array of methylated drug analogues.