Norbornadiene carbon atom reactions

It was also discovered that the exo-isomer was formed exclusively in the reaction (except in cases involving norbornadiene where the formed exoisomer underwent irreversible isomerisation to the entfo-isomer, catalysed by dicobalt octacarbonyl) and noted when the products are derived from unsymmetrical acetylenes (MeC=CH or PhC=CH) only a single position isomer is isolated... it is readily shown that the single substituent always occurs on the carbon atom adjacent to the carbonyl group , 3... 

Hexafluoro-2-butyne undergoes 1,4 addition by reaction with Rh(dik)(diolefin) (dik = acac, dpm, dbm diolefin = cod, norbornadiene), with formation of a C—C bond between the alkyne and the methyne carbon atom of the /3-diketonate. Additional trimer-ization of hexafluoro-2-butyne to hexakis(trifluoromethyl)benzene and /j -arene coordination of the latter to rhodium affords 103 (equation 73). 

The substituent effects of norbornadiene derivatives in the iridium-catalysed asymmetric 2 -I- 2-cycloaddition reactions with arylacetylenes have been investigated. Results have shown that the atom forming the short bridge chain had the greatest effect on the enantioselectivity of the reaction. Heteroatoms such as oxygen and nitrogen resulted in excellent enantioselectivity while a carbon atom on the bridge chain decreased the enantioselectivity. " ... 

Norbornadiene (463 g., 5.03 moles), distilled from calcium hydride, and 5% rhodium on carbon (2.S-4.5 g., 0.001-0.002 g.-atom of Rh, Engelhard Industries) are added and the mixture is stirred and refluxed for 1 day, and the rhodium on carbon is filtered. The filtrate is distilled at atmospheric pressure, yielding recovered norbornadiene and a distillation residue containing the reaction product. The procedure is repealed using the recovered norbornadiene, and the repetitions are continued until norbornadiene is consumed. 

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