MolSynapsequestion bank
MolSynapse / Question bank / Stereoisomerism / Cyclic stereoisomers (cyclopropane, cyclobutane, cyclohexane) from structures
JEE Main levelSingle correct optionDifficulty 2 of 3st311

The compound shown is 1-bromo-3-chlorocyclobutane with no configuration specified. Treating the ring as planar, which statement about its stereoisomers is correct?

  1. AThere are two stereoisomers, cis and trans, and both are achiral
  2. BThere are three stereoisomers: a meso cis form and a pair of trans enantiomers
  3. CThere are four stereoisomers, two pairs of enantiomers
  4. DThere is only one form, because C1 and C3 are not stereocentres

Answer: A

In 1-bromo-3-chlorocyclobutane the two ring paths from C1 to C3 are identical ( each), so C1 and C3 are not classical stereocentres: neither carries four different groups. The cis and trans arrangements are nevertheless different compounds (diastereomers). Each has a mirror plane containing C1, C3, Br and Cl, so both are achiral. Total = 2 stereoisomers, both optically inactive.
Practice Stereoisomerism More on Cyclic stereoisomers (cyclopropane, cyclobutane, cyclohexane) from structures
Previous questionNext question

More questions on Cyclic stereoisomers (cyclopropane, cyclobutane, cyclohexane) from structures