Final answer:
The question requires drawing the (R)-3-methoxyheptane molecule using dash–wedge notation to indicate stereochemistry, which involves identifying the chiral center, assigning priorities based on atomic number, and arranging substituents so that when the lowest priority group is at the back, the priority decreases in a clockwise fashion.
Step-by-step explanation:
The question asks for the structure of (R)-3-methoxyheptane using dash–wedge notation to designate stereochemistry. First, the straight-chain heptane is drawn with 7 carbon atoms. Then, at the third carbon, a methoxy group (OCH3) is attached. Since it is an (R)-enantiomer, we need to assign stereochemistry using the Cahn-Ingold-Prelog priority rules to find the configuration around the chiral center.
To determine if it's (R) or (S), we look at the four substituents attached to the chiral carbon (in this case, the third carbon in the chain), and assign priorities based on atomic number (highest to lowest). Once the priorities are assigned, we position the lowest priority group pointing away from us (represented with a dashed line) and the others in the plane or coming out of the plane (represented with wedges).
The fact that it is an (R) enantiomer means that when we look from the direction that places the lowest priority group (usually a hydrogen) at the back, the other groups will decrease in priority in a clockwise fashion. This means the methoxy group must be positioned in such a way that this condition is satisfied. The rest of the hydrogen and alkyl substituents on the chiral center are arranged accordingly.