Copper and In Situ-Generated Triflic Acid Relay-Promoted Four-Component Cascade Reaction for the Construction of Polysubstituted Cycloguanidines.

An unprecedented copper and in situ-generated triflic acid relay-promoted four-component cascade reaction of cyanamides, diaryliodonium triflates, propargylic amines, and HO was established for rapid and concise construction of diverse five-membered cycloguanidines. Copper-catalyzed guanidination/intramolecular hydroamination and in situ-generated HOTf-accelerated hydration proceeded sequentially with high level of chemoselectivity and regioselectivity, and six new bonds were simultaneously built in high yields. Thus, diaryliodonium triflates served not only as an arylation reagent but also as an internal acid promoter, establishing an alternative strategy for highly efficient utilization of diaryliodonium trifates.

Association between sequence variants in cadmium-related genes and the cadmium accumulation trait in thermo-sensitive genic male sterile rice.

Although cultivation of hybrid rice varieties has been increasing, there are risks that high levels of cadmium (Cd) will accumulate in grain when such rice is grown in Cd-polluted environments. To produce Cd-safe hybrid rice, one practical approach is the generation of low Cd-accumulating parental lines. In two-line hybrid breeding, thermosensitive genic male sterile (TGMS) lines function as female parents to yield hybrid seeds.