Question

Use the Cahn-Ingold-Prelog rules to rank the following groups in terms of priority 2. Use the Cahn-Ingold-Prelog rules to rank the following groups. In terms of priority 3. Use the Cahn-Ingold-Preiog rules to rank the following groups in terms of priority

Answer 1

Two groups are compared first by atomic number of the atoms directly attached to the stereocenter; the group having the atom of higher atomic number receives higher priority. If there is a tie, a list is made for each group of the atoms bonded to the one directly attached to the stereocenter, i.e., the atoms at distance 2 from the stereocenter. Each list is arranged in order of decreasing atomic number. Then the lists are compared atom by atom; at the earliest difference, the group containing the atom of higher atomic number receives higher priority. If there is still a tie, each atom in each of the two lists is replaced with a sub-list of the other atoms bonded to it (at distance 3 from the stereocenter), the sub-lists are arranged in decreasing order of atomic number, and the entire structure is again compared atom by atom. This process is repeated, each time with atoms one bond farther from the stereocenter, until the tie is broken.