Search

We have developed a synthetic strategy for Et3N‐promoted [5+3] cycloaddition reactions between acetoxypyranones and azomethine imines to access functionalized azabicyclo[3.3.1]alkenones with three tertiary stereocenters (31 examples, 36% to 87% yield, 5.5:1 to >20:1 dr). The method was scalable, and the products could be transformed to various eight‐membered‐ring bridged heterocyclic molecules. [ABSTRACT FROM AUTHOR]

By switching the position of the alkene and alkyne, a new type of 3-acyloxy-1,4-enyne (ACE) five-carbon building block was developed for Rh-catalyzed intramolecular [5+2] cycloaddition. An electron-withdrawing acyl group on the alkyne termini of the ACE was essential for a regioselective 1,2-acyloxy migration. This new method provided bicyclic [5.3.0]decatrienes that are different from previous methods because of the positions of the alkenes and the acyloxy group. Multiple mechanistic pathways become possible for this new [5+2] cycloaddition and they are investigated by computational studies. [ABSTRACT FROM AUTHOR]

The fuzzy symmetries of two kinds of linear polyacene molecules are probed into in the paper. In these molecules, any one of the benzene rings abreast connects at most other two rings in two ways: either its two opposite C-C bonds combine with two other rings, respectively, or its two meta-position C-C bonds connect two rings in cis- and trans-form, respectively. The former is called p-polyacenes (or straight polyacenes), and the latter is m-polyacenes (or kinked ones). It can be thought as the planar molecule with approximate one-dimensional space periodic transformation (parallel translation) symmetry, namely, group $${{\rm G}_{1}^{2}}$$ symmetry, when the number of its benzene ring is very large; on the other hand, it can be considered as the fuzzy group $${{\rm G}_{1}^{2}}$$ symmetry, if the benzene ring number is not large enough. The p-polyacene and m-polyacene with 20 benzene rings are analyzed as typical examples, and the energies of the π-molecular orbital (MO) and the fuzzy symmetry characters related to the space symmetry transformations are carefully examined. Moreover, the π-MOs of the p-polyacenes and m-polyacenes with different numbers of benzene ring are investigated to obtain the related rules. [ABSTRACT FROM AUTHOR]

A new type of ACE, i.e. [ABSTRACT FROM AUTHOR]

The utility of the method is exemplified by the preparation of a photoelectrically interesting multiphenyl compound [cf. [ABSTRACT FROM AUTHOR]