Expedient synthesis of a symmetric cycloheptyne-Co2(CO)6 complex for orthogonal Huisgen cycloadditions

A cycloheptyne dicobalt-carbonyl complex with a terminal alkyne was synthesized by a short procedure, and was able to react selectively in Strain Promoted Alkyne Azide Cycloaddition (SPAAC) or Copper Catalysed Alkyne Azide Cycloaddition (CuAAC) depending on the conditions.

Generation of cycloheptynes and cyclooctynes via a sulfoxide-magnesium exchange reaction of readily synthesized 2-sulfinylcycloalkenyl triflates

Cycloheptynes and cyclooctynes were efficiently generated via a sulfoxide-magnesium exchange reaction of readily synthesized 2-sulfinylcycloalkenyl triflates. Cycloadditions between various ynophiles and the cycloalkynes generated by this method proceeded efficiently, providing an easy method to prepare a wide range of heterocycles fused with seven- or eight-membered carbocycles.

En route to dinitroacetylene: nitro(trimethylsilyl)acetylene and nitroacetylene harnessed by dicobalt hexacarbonyl

Dinitroacetylene and other nitroacetylenes are attractive stoichiometric precursors to high energy-density materials, but suffer from high reactivity and thermal instability. Herein, we report that nitroacetylenes can be dramatically stabilized in the form of their dicobalt hexacarbonyl complexes. In particular, we describe the syntheses and characterization of the first two transition-metal complexes of nitroalkynes, [μ-1-nitro-2-(trimethylsilyl)ethyne-1,2-diyl]bis(tricarbonylcobalt)(Co-Co) and [μ-1-nitroethyne-1,2-diyl]bis(tricarbonylcobalt)(Co-Co). The chemistry of these compounds reveals their potential as reaction partners in [2+2+2] cyclotrimerizations, furnishing nitroindane, nitrotetralin, and trinitrobenzene products. The X-ray crystal structure of 1,3,5-trinitro-2,4,6-tris(trimethylsilyl)benzene presents a distorted, yet planar, aromatic ring.