Assign absolute configurations as R or S to each of the following compounds:(a) (b) (c) (d...

Assign absolute configurations as R or S to each of the following compounds:

(a)

(b)

(c)

(d)

Sample Solution (a) The highest ranking substituent at the chirality center of 2-methyl-1-butanol is CH2OH; the lowest is H. Of the remaining two, ethyl outranks methyl.

Order of precedence: CH2OH > CH3CH2 > CH3 > H

The lowest ranking group (hydrogen) points away from us in the drawing. The three highest ranking groups trace a clockwise path from CH2OH → CH3CH2 → CH3.

This compound therefore has the R configuration. It is (R)-(+)-2-methyl-1-butanol.