Asymmetric synthesis is best described as:

Asymmetric synthesis refers to the process of creating chiral molecules that favor the formation of one specific enantiomer over the other. This is significant in organic chemistry because enantiomers can exhibit vastly different biological activities; for example, one enantiomer of a drug may be therapeutically beneficial while the other could be harmful or inactive.

The hallmark of asymmetric synthesis is the ability to control the stereochemistry of the product, ensuring that one enantiomer predominates. Methods such as the use of chiral catalysts or chiral auxiliaries are often employed to achieve this selectivity, making it a powerful technique in the synthesis of pharmaceuticals and other biologically relevant compounds.

In contrast to other options, creating racemic mixtures involves generating equal amounts of both enantiomers, which is contrary to the goal of asymmetric synthesis. Similarly, the synthesis of achiral compounds does not involve chirality at all, and producing symmetrical compounds does not pertain to the selective synthesis of chiral molecules. This focus on enantioselectivity is what fundamentally defines asymmetric synthesis.