A novel and efficient approach to the synthesis of 2-vinylbenzylamines is reported. This involves obtaining 2-vinylbenzylamine ligands from tetrahydroisoquinoline by alkylation and reduction followed by the Hofmann cleavage. The resultant 2-vinylbenzylamines allowed us to obtain new Hoveyda–Grubbs catalysts, which were thoroughly characterised by NMR, ESIMS, and X-ray crystallography. The utility of this chemistry is further demonstrated by the tests of the novel catalysts (up to 10−2 mol %) in different metathesis reactions such as cross metathesis (CM), ring-closing metathesis (RCM) and ring-opening cross metathesis (ROCM).

The title diepoxyphenalene derivative, C17H18O6, comprises a fused cyclic system containing four five-membered rings (two dihydrofuran and two tetrahydrofuran) and one six-membered ring (cyclohexane). The five-membered dihydrofuran and tetrahydrofuran rings adopt envelope conformations, and the six-membered cyclohexane ring adopts a distorted chair conformation. Two methyl carboxylate groups occupy adjacent positions (2- and 3-) on a tetrahydrofuran ring. In the crystal, two pairs of C—H...O hydrogen bonds link the molecules to form inversion dimers, enclosing two R 2 2(6) ring motifs, that stack along the a-axis direction and are arranged in layers parallel to the bc plane.

Interactions of N-(propargyl)indole-2-carbonitrileswith nitrogen nucleophiles were studied. It was found that lithium hexamethyldisilazane (LiHMDS)-promoted reactions give mixtures of two product types, originating from an initial attack onto carbon−carbon or carbon−nitrogen triple bonds. Performing the reaction at reduced temperature and in the presence of catalytic amounts of LiHMDS delivered alkyne hydroamination products exclusively. On the contrary, the one-pot reaction of N-(propargyl)indole-2-carbonitriles with methanol and LiHMDS on heating, followed by the addition of a nitrogen nucleophile, allowed a selective domino cyclization sequence toward 1-aminopyrazino-[1,2-a]indoles. Anilines and nitrogen heterocycles could be employed as N-nucleophiles to obtain products of both types. Moreover, an alternative one-pot route toward a third product type has been developed. When N-(propargyl)indole-2-carbonitrile was first combined with aniline and LiHMDS at reduced temperature, further heating of the in situ generated hydroamination product led to the intramolecular cyclization into 1-imino-2-phenylpyrazino[1,2-a]indoles. Thus, chemodivergent transformations of the same starting material into three compound classes were investigated. The possible reaction routes were studied, and N-(allenyl)indole-2carbonitrile was identified as the key intermediate. Acyclic and cyclic products exhibit fluorescence emission in the blue to green range.