Deuteration Degree-Controllable Methylation via a Cascade Assembly Strategy using Methylamine-Water as Methyl Source.

We present a novel and effective photocatalytic method for the methylation of β-diketones with controllable degrees of deuterium incorporation via development of new methyl sources. By utilizing a methylamine-water system as the methyl precursor and a cascade assembly strategy for deuteration degree control, we synthesized methylated compounds with varying degrees of deuterium incorporation, showcasing the versatility of this approach. We examined a range of β-diketone substrates and synthesized key intermediates for drug and bioactive compounds with varying degrees of deuterium incorporation, ranging from 0 to 3.