Hydrogenation of Other Ring Systems

Replacement of one of the carbon atoms of the octalone ring system, as in compounds XXX, XXXI, and XXXII, by a nitrogen results in different hydrogenation stereochemistry, as shown in Table IV. It is possible that in the 

Percent cis Product Obtained on Hydrogenation of Heterocycles XXX, XXXI, and XXXII in Neutral and Acidic Media  

6Data from Durand-Henchoz and Morrau (43). Data from Augustine (13). 

The hydrogenation of hydrindenones with the unsaturated ketonic system in either the five- or six-membered ring (XXXIII and XXXIV) gives almost exclusive cis-product formation, regardless of the nature of the solvent used or the type of angular substituent present (22, 44-46). The presence of a substituent at the 4-position in 9-methyl-hydrind-4-ene-3-ones (XXXV) leads to preferential trans-isomer formation (45-48). The fact that the 4-substituent in the saturated 

Product Stereochemistry Obtained on Hydrogenation of Bicyclic Unsaturated Ketones in Acidic Medium  

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