The in vivo temperature monitoring of a microenvironment is significant in biology and nanomedicine research. Luminescent nanothermometry provides a noninvasive method of detecting the temperature in vivo with high sensitivity and high response speed. However, absorption and scattering in complex tissues limit the signal penetration depth and cause errors due to variation at different locations in vivo. In order to minimize these errors and monitor temperature in vivo, in the present work, we provided a strategy to fabricate a samewavelength dual emission ratiometric upconversion luminescence nanothermometer based on a hybrid structure composed of upconversion emissive PbS quantum dots and Tm-doped upconversion nanoparticles. The ratiometric signal composed of two upconversion emissions working at the same wavelength, but different luminescent lifetimes, were decoded via a time-resolved technique. This nanothermometer improved the temperature monitoring ability and a thermal resolution and sensitivity of~0.5 K and~5.6% K −1 were obtained in vivo, respectively.

A comprehensive and updated summary of asymmetric organocatalytic annulation reactions is presented; in particular, the applications of these annulation strategies to natural products synthesis are highlighted.

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A highly diastereo- and enantioselective phosphine-catalyzed sequential [3 + 2]/[3 + 2] annulation of allenoates with arylidenemalononitriles has been developed. This reaction allows for the facile construction of multifunctionalized cis-fused bicyclic­[3,3,0]­octene scaffolds, encompassing three consecutive stereogenic centers with one quaternary carbon center, in a one-step operation from readily available materials. The reported protocol is scalable, operates under mild reaction conditions, and creates the core structural motif of a number of natural products.

C-4-selective functionalization of azlactones provides access to α,α-disubstituted unnatural α-amino acids, which has been extensively investigated in the past decades. However, a vast majority of such transformations are two-electron transfer reactions. Herein, leveraging on the persistent radical effect, we develop photocatalytic energy transfer-enabled regioconvergent alkylation of azlactones with redox-active esters via radical–radical couplings. This strategy is extended to the utilization of simple alkanes as the radical precursors, whereby the aryl redox-active esters play a dual role of an oxidant and a hydrogen-atom-transfer agent. Notably, the excited state Ir(III) photocatalyst enables selective activation of the unwanted imine products through triplet energy transfer, delivering C-4-functionalized azlactones with high regioselectivity. Both experimental investigations and density functional theory calculations on the reaction mechanism were performed, supporting EnT-enabled regioconvergent photocatalytic radical–radical coupling reaction pathways.