Question

Draw a perspective formula for each of the following:

a. (S)-2-chlorobutane

b. (R)-1,2-dibromobutane

Short answer

a.

b.

Step-by-step solution

Definition of Perspective formulae

Perspective formulae are chemical compounds that have their components orientated in three dimensions. The Fischer projection is another name for it.

Subpart (a) Steps to draw the Perspective formula of (S)-2-chlorobutane.

• A perspective formula of (S)-chlorobutane.

• For drawing the formula, first draw the bonds around the asymmetrical center first. (Keep in mind that the solid and hatched wedges must be contiguous, and the solid wedge must be below the hatched wedge.)

• On the hatched wedge, place the group with the lowest priority. Any residual bond should be assigned to the group with the greatest priority.

• Draw an arrow anticlockwise from the group with the highest priority to the next accessible bond, and place the group with the second-highest priority on that bond because you've been instructed to draw the S enantiomer.

Steps to draw the Perspective formula of (R)-1,2-dibromobutane.

• A perspective formula of (R)-bromobutane.

• For drawing the formula, first draw the bonds around the asymmetrical center first. (Keep in mind that the solid and hatched wedges must be contiguous, and the solid wedge must be below the hatched wedge).

• On the hatched wedge, place the group with the lowest priority. Any residual bond should be assigned to the group with the greatest priority.

• Now, draw an arrow counter-clockwise from the group with the highest priority to the next accessible bond and place the group with the second-highest priority on that bond because you've been instructed to draw the R enantiomer.