Schinortriterpenoids: A Case Study in Synthetic Design

Since the pioneering days of total synthesis and retrosynthetic analysis, the community has embraced guiding principles for planning synthetic approaches towards complex natural products. These guideposts have enabled the community to synthesize ever more complex compounds by applying prior knowledge gained in new settings. The recently isolated schinortriterpenoid family of natural products has attracted considerable synthetic attention and provided a rich opportunity to evaluate the lessons learned in the construction of complex, polycyclic scaffolds. In this Minireview, a detailed discussion of the synthetic work within this family is provided, including the six reported total syntheses, as well as a comparative analysis of the approaches utilized in their construction.     

Calculation of the vibration–rotational transition intensities of water molecules trapped in an argon matrix: stretching O–H vibrations spectral region

The frequencies and intensities of vibration–rotational transitions of water molecules in an argon matrix were calculated for temperatures of 6 and 30 K. The rigid asymmetric top approximation was used with available literature values of the effective rotational constants in the ground and excited vibrational states. The calculations were carried out by taking into account the existence of a non-equilibrium population distribution between the rotational levels of ortho- and para-water isomers. It was assumed that the temperature relaxation of the population of rotational levels is independent of the ortho- and para-isomers. Comparison of the results of the theoretical calculations with experimental literature data shows good agreement for the majority of the rotational structure lines for symmetric and antisymmetric stretching vibrations both in the frequency values and in the values of the relative intensities.     

Aerobic asymmetric oxygenation catalysis: a well forgotten… future?

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Recent Advances and Perspectives of Transition Metal‐Catalyzed Asymmetric Fluorination Reactions

The synthesis of fluorine‐containing molecules has received intensive attention in recent years due to the great value of fluorides, however, the transition metal‐catalyzed asymmetric construction of C—F bonds is much less developed. This review presents the recent advancement of transition metal‐catalyzed asymmetric fluorination reactions, in which the final C—F bond is from reductive elimination of organometallic complexes. In addition, the perspective of the field is also provided for the future studies of asymmetric fluorinations and the related transformations, such as trifluoromethylation, trifluoromethylthiolation and trifluoromethoxylation.