Allylpotassium is an organopotassium compound with the molecular formula . It is a colorless, extremely air-sensitive compound that is usually generated and handled in solution. It is synthesized by metalation of propylene with Schlosser's base, a mixture of potassium tert-butoxide and butyl lithium:
Consistent with its extreme air-sensitivity, allylpotassium is highly nucleophilic. For example, it adds to pyridine, allowing the synthesis of 4-allyl-1,4-dihydropyridines. Trimethylsilyl-substituted allylpotassium have been characterized by X-ray crystallography