Hydrogen bond-assisted 1,2-cis O-glycosylation under mild hydrogenolytic conditions

A hydrogen bond-assisted α-selective glycosylation reaction by using 4,6-dibenzyloxy-1,3,5-triazin-2-yl(DBT) β-glycosyl donors was developed for the efficient construction of 1,2-cis-α-glycosidic bond in natural products. This method was applied successfully to the direct synthesis of complex oligosaccharidederived glycolipids with simple protecting chemistry. Mechanistic studies using the NMR spectroscopy and DFT calculation provide a proof of concept for hydrogen bond-assisted glycosylation reaction towardsα-specific construction of O-glycosidic linkage.

An Easy‑to‑Prepare Flexible Dual‑Mode Fiber Membrane for Daytime Outdoor Thermal Management

Excellent outdoor thermal management is vital for public health and safety.However,the ever-changing and uncontrol-lable outdoor environmental conditions,such as irrepressible sunlight and drastic temperature fluctuations,bring majestic challenges to outdoor thermal management.Here,we report a significant advancement toward designing and fabricating a novel fiber membrane with a dual-function of radiative cooling and solar heating for an efficient daytime outdoor thermal management.Unlike the reported dual-mode thermal management materials,which are usually fabricated by compounding organic polymers and metal/inorganic non-metal materials,our fiber-based membrane is composed of only two polymers,i.e.,poly(vinylidene fluoride-co-hexafluoropropene)(PVDF-HFP)and polypyrrole(PPy).The resulting membrane presents outstanding outdoor thermoregulation capacity,with a practically attainable sun-ambient cooling temperature of~4.5℃,super-ambient heating temperature of~35.8℃,in an outdoor environment,under solar intensity(Isolar)of~850 W m^(-2).Fabrication process is simple and cost-effective,which offers the possibility of preparing large-scale products.Owing to the scalable and simple fabrication process,and the exceptional outdoor thermoregulation ability,this dual-mode fiber membrane has great potential to maintain a comfortable outdoor environment for human activities and industrial operations.