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Herein, an I2‐catalyzed unprecedented cycloisomerization of ynamides is developed, furnishing various functionalized bis(indole) derivatives in generally good to excellent yields with wide substrate scope and excellent atom‐economy. This protocol not only represents the first molecular‐iodine‐catalyzed tandem complex alkyne cycloisomerizations, but also constitutes the first chemoselective cycloisomerization of tryptamine‐ynamides involving distinctively different C(sp3)−C(sp3) bond cleavage and rearrangement. Moreover, chiral tetrahydropyridine frameworks containing two stereocenters are obtained with moderate to excellent diastereoselectivities and excellent enantioselectivities. Meanwhile, cycloisomerization and aromatization of ynamides produce pyrrolyl indoles with high efficiency enabled by I2. Additionally, control experiments and theoretical calculations reveal that this reaction probably undergoes a tandem 5‐exo‐dig cyclization/rearrangement process. [ABSTRACT FROM AUTHOR]

A rhodium-catalyzed [4 + 2] cycloaddition of ynamines and 2-(cyanomethyl)phenylboronates has been developed, leading to efficient and excellent regioselective synthesis of valuable indole-linked aromatic compounds in a concise and flexible approach. Interestingly, this strategy was successful in the construction of C···N axially chiral indoles with high enantiocontrol by the introduction of a new phosphoramidite ligand (Xie-Phos).

Here, an Ir/Zn-cocatalyzed atroposelective [2+2+2] cycloaddition of 1,6-diynes and ynamines was developed, forging various functionalized C─N axially chiral indoles and pyrroles in generally good to excellent yields (up to 99%), excellent chemoselectivities, and high enantioselectivities (up to 98% enantiomeric excess) with wide substrate scope. This cocatalyzed strategy not only provided an alternative promising and reliable way for asymmetric alkyne [2+2+2] cyclotrimerization in an easy handle but also settled the issues of previous [Rh(COD) 2 ]BF 4 -catalyzed system on the construction of C─N axial chirality such as complex operations, limited substrate scope, and low efficiency. In addition, control experiments and theoretical calculations disclosed that Zn(OTf) 2 markedly reduced the barrier of migration insertion to significantly increase reaction efficiency, which was distinctly different from previous work on the Lewis acid for improving reaction yield through accelerating oxidative addition and reductive elimination.

Background: The coronavirus disease 2019 (COVID-19) caused by novel coronavirus 2019 in December 2019 has spread all around the globe and has caused a pandemic. There is still no current effective guidance on the clinical management of COVID-19. Mesenchymal stem cell therapy has been shown to be one of the therapeutic approaches to alleviate pneumonia and symptoms through their immunomo-dulatory effect in COVID-19 patients., Case Summary: We describe the first confirmed case of COVID-19 in Hangzhou to explore the role of human menstrual blood-derived stem cells (MenSCs) in the treatment of COVID-19. Moreover, we review the immunomodulation effect including non-specific and specific immune functions of MenSCs for the therapy of COVID-19., Conclusion: MenSCs can be helpful to find a promising therapeutic approach for COVID-19., Competing Interests: Conflict-of-interest statement: The authors declare no conflicts of interest related to this manuscript., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)