The present invention is directed to Benzomorphan Analog compounds of the Formula I", Formula IA", Formula IB", Formula IC", or Formula ID" as shown below； and related Formula I', Formula IA', Formula IB', Formula IC', or Formula ID'； Formula I, Formula IA, Formula IB, Formula IC, or Formula ID；wherein R1, R2a, R2b, R3 and R4 are as defined hereinCompounds of the Invention are useful for treating pain, constipation, and other conditions modulated by activity of opioid and ORL-1 receptors.
