γ-Substituted Vinylidene, Chroman-2-ylidene, and Hexahydrochromen-2-ylidene from Ruthenium Allenylidene/Alkenylcarbyne Complexes

Furo[3,2-c]coumarins carrying carbon substituents at C-2 and/or C-3. Isolation, biological activity, synthesis and reaction mechanisms

The isolation, biological activity and synthesis of natural furo[3,2-c]coumarins are presented, covering mainly the developments in the last 35 years. The most relevant approaches toward the synthesis of 2-substituted, 3-substituted and 2,3-disubstituted heterocycles are also discussed, with emphasis on the efficiency of the processes and their mechanisms.

Carbon-rich cyclopentadienyl ruthenium allenylidene complexes

Ruthenium allenylidene complexes based on carbon-rich polyaromatic moieties have been synthesized with interesting intermolecular π-interactions.

Preparation of pyranylidene complexes of ruthenium

Dimerization of alkylpropiolate on the half-sandwich fragment [Ru(η⁵-C₅H₅)(PPh₃){P(OMe)₃}]⁺ affords pyranylidene derivatives.