bridged bicyclic compounds and bad stereo depictions

Please see the image. If a user draws a hashed bond and a bold bond originating at a tetravalent C atom, and they fall on opposite sides of the line defined by the two plain bonds coming from the C atom, then the configuration of the central C atom should not be calculable, as correctly shown in the first structure. But, if you look at the second structure, Marvin incorrectly assigns a configuration to such a C atom when it is a bridgehead. Furthermore, deleting the bridgehead H atom causes the structure then to have the opposite configuration from when the bridgehead H atom is present, which is very confusing. 

I think the optimal solution is to treat the second structure like the first one, and to not assign a configuration at all to the bridgehead C atom. However, if you must assign a configuration, please have it match the one in the third structure.

Hi Bob,

Thanks for the report, we just working on a new stereo calculator, I think it will solve the problem.

János

Hi Bob,

If I take the molecules from left to right and comment just the top carbon atom:

The first one has no stereochemistry recognised as the wedges are contradictory.

The middle one is similar situation to the first one, it has contradictory wedges, but in this case one wedge is in ring and the other is in chain. We recognise the stereochemistry as the ligand (explicit H) wedge arrangement is taken into account over the wedge defined in the ring. It is the same situation as you would get if you delete the wedge from the ring bond.

The last one has recognised stereochemistry as there is no contradiction.

This is the current situation and as far as I understand correctly you would suggest to change the rule.

Would you expect not to neglect the ring bond if contradictory information appears?

If there is contradictory information, I think it is best by far not to assign any configuration at all. In other words, I think you should treat case 2 like case 1.

But, if someone held a gun to my head and forced me to assign configuration to case 2, I would use the C-C stereo bond to assign the configuration, not the C-H stereo bond.

Thank you for the information.

This issue is highly related to the one mentioned in the other forum topic.

They will be fixed together.