Bicyclo 3.2.1 octane-6-carbaldehydes

Chiral hydroformylation reactions have been studied using the tetranu-clear ruthenium cluster H4Ru4(CO)g(R,R-DIOP)2. The hydroformylation of bicyclo[2.2.2]oct-2-ene (toluene, 140°C, 100 bar, CO/H2=l) yields bicyclo [2.2.2.]octane-2-carbaldehyde with 51% conversion in an optical purity of 1.2% for the R-enantiomer (the catalytic turnover was not given)... 

Prolonged reaction times favor the formation of the exo-isomers. An initial rearrangement of the exo-epoxides into the bicyclic entfo-carbaldehydes followed by a slower but competitive endo to exo epimerization were suggested and verified by utilizing H NMR spectroscopy to follow the rearrangement. In the same way, heating e/z /o-7,8-epoxybicyclo[4.2.0]octane with lithium iodide in diethyl ether at 38 °C for 16 hours produced bicyclo[4.1.0]heptane-exo-7-carb-aldehyde. 

Reaction. with Lithium Thiocyanate. To LiSCN (153 mg, 2.3 mmol) in anhyd Et O (1 mL) was added exo-7,8-epoxybicyclo[4.2.0]octane (166 mg, 1.3 mmol). The flask was stoppered and stirred at 4L C for 34 h. Workup as described above gave the product yield 150 mg (90%), whose H NMR spectrum was consistent with that of known bicyclo[4.1.0]heptane-en<7o-7-carbaldehyde and displayed no cxo-aldchyde signal at 5 = 9.1. Air oxidation of the carbaldehyde gave an acid identical with authentic bicyclo[4.1.0]hep-tane-enrfo-7-carboxylic acid. ... 

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