RCHCHOH

RCHCHOH is not a defined chemical compound but a generic structural fragment used in organic chemistry to denote a carbon atom bearing a hydroxyl group (CHOH) attached to a substituent represented by R. The notation emphasizes a secondary alcohol motif, typically written as R−CH(OH)−R′ in reaction schemes, where R and R′ denote alkyl, aryl, or other substituents. It appears in discussions of oxidation-reduction chemistry, reductions of ketones, and the formation of secondary alcohols.

In practice, many secondary alcohols have the general formula R−CH(OH)−R′. When the two carbon substituents differ, the hydroxyl-bearing carbon becomes a stereocenter, allowing for enantiomeric forms (R and S configurations). Common examples illustrating the fragment include isopropanol (R = CH3, R′ = CH3) and 1-phenylethanol (R = Ph, R′ = CH3).

The fragment is frequently used as shorthand in mechanism diagrams, enzymatic steps, and textual descriptions to indicate an alcohol-bearing carbon adjacent to other carbon-containing groups. The properties and reactivity of any specific instance depend on the actual substituents R and R′; as a class, secondary alcohols exhibit hydrogen bonding, polarity, and a range of boiling points influenced by their substituents. See also alcohol, secondary alcohol, and stereochemistry.