<p id="p00005">Bioorthogonal chemistry refers to chemical reactions that can be carried out in biological systems without interfering with natural biochemical processes. During the past two decades since its emergence, the scope of bioorthogonal chemistry has been greatly expanded from ligation to cleavage reactions, with broad applications ranging from live cells to animals for biological studies, medical as well as pharmaceutical research. Chinese chemical biologists have actively participated in this exciting area, and a series of important work has been carried out with notable achievements. In particular, the creation and development of bioorthogonal cleavage reactions and its diverse applications have drawn considerable attentions. In this review, we summarize the representative work on bioorthogonal chemistry that been developed in China in recent five years. These works will be categorized into metal-, photo- and small molecule-mediated bioorthogonal ligation as well as cleavage reactions, respectively. In the end, we will discuss the future development along this exciting avenue and the further innovation of the &#x0201c;remote-control bioorthogonal chemistry&#x0201d;, which may eventually drive the bioorthogonal reactions into living animals or even human being.</p>

The controlled synthesis of calcium carbonate particles surface-functionalized with azido groups and its subsequent copper-catalyzed alkyne-azide cycloaddition (CuAAC) reactions with organocatalysts bearing alkyne anchors allowed the preparation of novel catalytic materials. A calcium carbonate-supported α,α-diarylprolinol silyl ether prepared in this manner catalyzes Michael addition of aldehydes to trans-β-nitrostyrenes with very high diastereo- and enantioselectivity. The immobilized catalyst can be recovered by simple decantation and reused. In addition, this heterogeneous catalytic system can also be adapted to continuous-flow operation, affording a five-fold productivity increase in comparison with the batch process.

A catalytic system to synthesize α-amino amides from isocyanates and ketimines has been developed using visible light iridium photoredox catalysis via umpolung reactivity of ketimines. Cross-couplings between diverse ketimine and isocyanate substrates have been evaluated, affording the desired α-amino amide products in good yields. In addition, a metal-free catalytic system using perylene and N,N-diisopropylethylamine has been developed. Finally, single-step synthesis of the psychoactive drug benzodiazepine-2-one analogue from one of the coupling products has been achieved, indicating the great application potential of the synthetic method developed herein.