Hexacarbonyl dicobalt tetrafluoroborate: Cobalt

Hexacarbonyl(1-methyl-2-propynylium)dicobalt tetrafluoroborate Cobalt(1+), hexacarbonyl[y-[2,3,-n 2,3-n)-l-methyl-2-propynylium]]di-, (Co-Co), tetrafluoroborate(l-) (10) (62866-98-2)... 

Nicholas published an Organic Syntheses paper highlighting the preparation of 2-(l-methyl-2-propynyl)cyclohexanone (65) from the reaction of 1-trimethylsiloxycyclohexene (62) with hexacarbonyl (l-methyI-2-propy-nylium)dicobalt tetrafluoroborate (63) and subsequent decomplexation of cobalt complexed alkyne 64. This report also includes procedures for the synthesis of the two starting materials (62 and 63). ... 

Tyrrell demonstrated a three step tandem sequence involving an intermolecular Nicholas reaction, intramolecular Nicholas reaction, and a cationic cyclization. Treatment of silyl enol ether 55 with hexacarbonyl(propiolaldehyde diethyl acetal) dicobalt and boron trifluoride provides cobalt-alkyne complex 56. Exposure of this material to tetrafluoroboric acid promotes an intramolecular Nicholas reaction to form the second six-membered ring. Alkyne decomplexation with ceric ammonium nitrate enables the final cyclization step to yield the target tricycle 57." ... 

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