A highly efficient, tetrakis(acetonitrile)copper(I) hexafluorophosphate [Cu ACHTUNGTRENNUNG(MeCN)4PF6]catalyzed tandem Cu(I)-carbene N H insertion/ Cu(I)-catalyzed hydroamination of alkynes, which leads to sequential formation of two C N bonds to yield isoindole derivatives, has been developed.

In the title compound, C(14)H(8)INO(2), the dihedral angle between the isoindole ring and the phenyl ring of the 1-iodo-benzene group is 84.77 (15)°. There is a short inter-molecular I⋯O contact of 3.068 (3) Å in the crystal.

In the title mol-ecule, C(21)H(20)N(2)O(4), the dihedral angle between the phenol ring and the isoindole-1,3-dione mean plane is 69.79 (6)°. The cyclo-hexane ring adopts a chair conformation. Weak inter-molecular O-H⋯O and O-H⋯N inter-actions feature as part of the crystal packing.

In the title mol-ecule, C(30)H(32)N(2)O(2), the two tolyl rings form dihedral angles of 65.8 (1) and 6.6 (1)° with the isoindole-1,3-dione mean plane. The cyclo-hexane ring adopts a chair conformation.

The asymmetric unit of the title compound, C11H11ClN2, contains two almost-planar independent mol-ecules: the isoindole and dimethyl-amino-methyl-ene mean planes in the two mol-ecules form dihedral angles of 5.45 (8) and 1.34 (8)°. The crystal packing exhibits no short inter-molecular contacts, except for a relatively short Cl⋯Cl distance of 3.4907 (7) Å.

The title compound {systematic name: 2-[(3,5-dimenthylpyrazol-1-yl)meth-yl]isoindole-1,3-dione}, C(14)H(13)N(3)O(2), was prepared by reaction of N-(bromo-meth-yl)phthalimide and 3,5-dimethyl-pyrazole in chloro-form solution. The mol-ecular structure and packing are stabilized by intra-molecular C-H⋯O hydrogen-bonding and C-H⋯π inter-actions.

A synthetic approach to the 6-methyl-3,4-dihydropyrazinone core from Ugi adducts is described. This methodology relies on the regioselective C-N bond formation between an allenamide moiety at C-β and an amide anion formed under base-mediated conditions. This protocol allows easy access to tricyclic systems such as pyrazino[2,1-a]isoindole and pyrazino[2,1-a]isoquinoline nuclei.