Chemical Properties
clear light yellow liquid
Uses
1-Pyrrolidino-1-cyclohexene is a cyclic enamine that is used as an electron-rich dienophile in synthetic reactions.
Synthesis Reference(s)
Chemical and Pharmaceutical Bulletin, 16, p. 1466, 1968
DOI: 10.1248/cpb.16.1466
Reactivity Profile
The enamine nitrogen and its β-carbon atom are nucleophilic, undergoing substitution or conjugate addition; they can take part in 1,2- or 1,4-cycloadditions; iminium salts act as electrophiles.
Synthesis
The most commonly used preparation method for these enamines is the acid-catalyzed condensation of a secondary amine with cyclohexanone. An example is the reaction of Pyrrolidine with cyclohexanone (eq 1). Using a preformed Titanium(IV) Chloride-amine complex with cyclohexanone greatly decreases the reaction time while maintaining high yields. This technique is also effective with functionalized cyclohexanones. When unsymmetrical tin(II) amides are allowed to react with cyclohexanone, good yields of enamines result.
Precautions
Readily reacts with water or atmospheric oxygen; should be stored under dry nitrogen.
