(R)-Phenylephrine (depicted herein as compound (1)) is an α1-adrenergic receptor agonist used as a decongestant, a pupil dilator and to increase blood pressure.

Phenylephrine is used as a substitute for pseudoephedrine (e.g., Pfizer's Sudafed®). Phenylephrine is a selective α-adrenergic receptor agonist and does not cause the release of endogenous noradrenaline. Phenylephrine is less likely to cause side-effects such as central nervous system stimulation, insomnia, anxiety, irritability, and restlessness.
Various chemical reaction methods have been described for the synthesis of phenylephrine. U.S. Pat. No. 6,900,203 describes a synthetic route to phenylephrine that includes a chiral addition of cyanide to a ring-fluorinated phenaldehyde intermediate using hydroxynitrile lyase enzyme. No routes to phenylephrine have been described involving a stereoselective reduction using a ketoreductase.