A Pd-catalyzed asymmetric allylic amination of 4-substituted 2-acetoxybut-3-enoates with amines has been developed for the regiospecific synthesis of chiral α,β-unsaturated γ-amino esters. The desired chiral aminated products can be obtained in up to 98% yield, and 99% ee and can be conveniently transformed to chiral γ-amino acid/alcohol derivatives and chiral γ-lactams, which can then be subjected to the synthesis of several types of chiral drugs and drug candidates. The preferential formation of chiral γ-amino esters may be attributed to the bulky substituents on the right side of the allyl substrates. This work provides an efficient strategy for the synthesis of chiral α,β-unsaturated γ-amino esters and their derivatives.

Asymmetric hydrogenation of various α-substituted acrylic acids was carried out using RuPHOX-Ru as a chiral catalyst under 5 bar H2, affording the corresponding chiral α-substituted propanic acids in up to 99% yield and 99.9% ee. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to 5000 S/C), and the resulting product (97%, 99.3% ee) can be used as a key intermediate to construct bioactive chiral molecules. The asymmetric protocol was successfully applied to an asymmetric synthesis of dihydroartemisinic acid, a key intermediate required for the industrial synthesis of the antimalarial drug artemisinin.

5-Formylcytidine (f 5 C) is one type of post-transcriptional RNA modification, which is known at the wobble position of tRNA in mitochondria and essential for mitochondrial protein synthesis. Here, we show a method to detect f 5 C modifications in RNA and a transcriptome-wide f 5 C mapping technique, named f 5 C-seq. It is developed based on the treatment of pyridine borane, which can reduce f 5 C to 5,6-dihydrouracil, thus inducing C-to-T transition in f 5 C sites during PCR to achieve single-base resolution detection. More than 1000 f 5 C sites were identified after mapping in Saccharomyces cerevisiae by f 5 C-seq. Moreover, codon composition demonstrated a preference for f 5 C within wobble sites in mRNA, suggesting the potential role in regulation of translation. These findings expand the scope of the understanding of cytosine modifications in mRNA.

A rapid and divergent access to chiral azacyclic nucleoside analogues has been established via highly exo-selective and enantioselective 1,3-dipolar cycloaddition of azomethine ylides with β-nucleobase substituted acrylates. Using 1 mol% of a chiral copper complex, various chiral azacyclic nucleoside analogues were obtained in high yields, excellent exo-selectivities and enantioselectivities (98 to >99% ee).

CuBr was found to be an efficient catalyst for the C-N cross coupling reaction of purine and diaryliodonium salts. 9-Arylpurines were synthesized in excellent yields with short reaction times (2.5 h). The method represents an alternative to the synthesis of 9-arylpurines via Cu(II) catalyzed C-N coupling reaction with arylboronic acids as arylating agents.

An efficient one‐pot method for the synthesis of various C6‐alkylthio‐substituted purine nucleosides has been developed under microwave irradiation with good to excellent yields without any metal catalyst (see scheme). This process expands the scope of existing synthetic methodologies and was further successfully applied for synthesis of the biologically important compound 4‐nitrobenzylthioinosine (NBTI).

A new P-stereogenic PNP pincer-Pd complex was readily prepared from optically pure 2,6-bis[(boranato(tert-butyl)methylphosphino)methyl]pyridine. It was used in the asymmetric intramolecular hydroamination of amino-1,3-dienes, with the desired products being obtained in good yields and with excellent regioselectivities and up to moderate enantioselectivities. The absolute configuration of one of the hydroamination products was determined by X-ray crystallography studies. This simple and efficient procedure can be used for the synthesis of allyl-type chiral pyrrolidine derivatives.

Highly enantioselective [5 + 4] annulations of ortho-quinone methides with vinylethylene carbonates are enabled by asymmetric palladium catalysis for the synthesis of chiral nine-membered benzo-heterocycles.