Photoactivated silicon–oxygen and silicon–nitrogen heterodehydrocoupling with a commercially available iron compound†
Silicon–oxygen and silicon–nitrogen heterodehydrocoupling catalyzed by the commercially available cyclopentadienyl dicarbonyl iron dimer [CpFe(CO)2]2 (1) under photochemical conditions is reported. Reactions between alcohols and PhSiH3 with catalytic 1 under visible-light irradiation produced silyl ethers quantitively. Reactions between either secondary or tertiary silanes and alcohols also produced silyl ethers, however, these reactions were marked by their longer reaction times and lower conversions. Reactions of either primary or secondary amines and silanes with catalytic 1 demonstrated mixed efficiency, featuring conversions of 20–100%. Mechanistic study indicates that an iron silyl compound is unimportant in the bond-formation step and argues for either a nucleophilic alkoxide or amide intermediate. Most important, mechanistic study reveals that the most immediate hurdle in the catalysis is the poor activation of 1, demonstrating the necessity to fully activate the catalyst to realize the potential of iron in this reactivity.