Which of the following ligands has the highest priority according to `CIP` sequence rule?

Options

A. Pheny`1`
B. Cyclohexy`1`
C. `t-`Buthy`1`
D. Isobuthy`1`

Answer

A

Explanation

The correct priority sequence is phey`1 gtt-` buthy`1 gt` cyclohexy`1 gt` isobuty`1`. Pheny`1 gt` cyclochexy`1` because the pheny`1C` is doubly bonded and counted as attached to three `C's.t-`Buthy`1gt`cyclohexy`1` because the carbon atom is bonded to the three methy`1` groups while in cyclohexy`1` the carbon atom is bonded to two `CH_(2)`units and one hydrogen atom. Pheny`1 gt(CH_(3))_(3)C` becasue in Pheny`1`next carbon atom carries `(C,C,H)` while in `t-`buty`1`next carbon carries `(H,H,H).` Cyclohexy`1 gt (CH_(3))_(2)CH` becasue the once-removed methy`1` carbon atoms each have three hydrogens while the once-removed ring carbon atoms each have two hydrogents and another ring carbon atom.