Final answer:
The organometallic reagent that forms 1,4-addition products is Potassium Osamate.
Step-by-step explanation:
The organometallic reagent that forms 1,4-addition products is Potassium Osamate. 1,4-addition is a type of nucleophilic addition reaction in which the nucleophile adds to the carbon atom at the 1 position and the electrophile adds to the carbon atom at the 4 position of an alkene or alkyne. Potassium Osamate is commonly used in the synthesis of cyclic compounds such as diols and cyclic sulfates.