Hydrogen transfer-triggered C(sp3)−C(sp3) cleavage of 1,3-diols for mono-N-methylation of primary amines

Replacing non-renewable fossil resources with sustainable biomass feedstocks represents one of the central missions of modern chemistry. This shift inevitably places urgent demands on chemical methods for biomass degradation, particularly for the efficient and selective cleavage of unstrained C(sp³)-C(sp³) bonds that constitute the backbone of biomass molecules. Herein, 1,3-propanediol, a low-cost biomass-derived bulk chemical, is established as an efficient, green, and sustainable C₁ source for the mono-N-methylation of primary amines via chelation-free C(sp³)-C(sp³) bond cleavage. This method features high mono-N-methylation selectivity, low catalyst loading, wide substrate scope, and mild conditions. Unlike the traditional C-C bond cleavage strategies to avoid the involvement of hydrogen transfer, this reaction instead leverages a hydrogen transfer-triggered N-hydroxyalkylation/retro-Mannich fragmentation pathway to facilitate the scission of unstrained C(sp³)-C(sp³) bond in primary 1,3-diols. This work is anticipated to stimulate innovation in developing new C-C bond cleavage strategies for biomass degradation.