Question 13.3: Fischer Projections Determine if each Fischer projection is ...
Fischer Projections
Determine if each Fischer projection is chiral or achiral. If chiral, identify it as the D or L stereoisomer and draw the mirror image.
a. \begin{array}{r c}\begin{matrix} \quad CH_2OH \end{matrix} \\ \begin{matrix} HO \end{matrix} \begin{array}{r|c} \begin{matrix} \\ \end{matrix} & \begin{matrix} \\ \end{matrix} \\ \hline \begin{matrix} \\ \end{matrix} & \begin{matrix} \\ \end{matrix}\end{array}H \\\begin{matrix}\quad \quad \ CH_3 \end{matrix}&&&&&& b. \begin{matrix} \quad CH_3 \end{matrix} \\&&&&&& \begin{matrix} HO \end{matrix} \begin{array}{r|c} \begin{matrix} \\ \end{matrix} & \begin{matrix} \\ \end{matrix} \\ \hline \begin{matrix} \\ \end{matrix} & \begin{matrix} \\\end{matrix}\end{array}H \\&&&&&&\begin{matrix}\quad \quad \ CH_3 \end{matrix}\end{array}
a. Chiral. The carbon at the intersection is attached to four different substituents. It is the L stereoisomer because the —OH group is drawn on the left. The mirror image is drawn by reversing the —H and —OH groups on the chiral carbon.
\begin{matrix} \quad CH_2OH \end{matrix} \\ \begin{matrix} H \end{matrix} \begin{array}{r|c} \begin{matrix} \\ \end{matrix} & \begin{matrix} \\ \end{matrix} \\ \hline \begin{matrix} \\ \end{matrix} & \begin{matrix} \\ \end{matrix}\end{array}OH \\\begin{matrix}\quad \ CH_3 \end{matrix}b. Achiral. The carbon atom at the intersection is attached to two identical groups (-CH_{3}).