Microwave Synthesis of Benchmark Organo-iron complexes
Microwave Synthesis of Benchmark Organo-iron complexes
Chem 347/447
“Microwave synthesis of benchmark Organo-iron complexes” is an interesting article by Sean M. Garringer , Andrew J. Hesse , John R. Magers , Kristopher R. Pugh , Stacy A. O’Reilly and Anne M. Wilson which describes microwave- assisted technique in chemical synthesis. The authors detail the formation of various organo-iron species with the aid of a microwave. Using microwaves in chemical synthesis has resulted in not only decreased reaction time as well as maintained or improved yields when compared to traditional methods. Synthesis of organometallic compounds usually requires long time at elevated temperatures and these reaction conditions are optimal to exploit microwave assisted synthesis. The target compounds are the three classes of Organo-iron complexes which are sandwich complexes, cyclopentadienyl carbonyl complexes and phosphine tricarbonyl complexes. Several compounds from these classes were studied and it was found that refluxing time was reduced to few minutes from several hours, improving yields of some poor yielding compounds. The article describes in detail six schemes or synthesis of six different complexes using microwave and how it differed from the traditional synthetic method. In the Scheme 1 ferrocene was synthesized. Traditional way required reaction conditions of 175oC for 45 min and had 20% yields, whereas the first trial of microwave synthesis or one-pot synthesis had a yield of 40-70%. However, this synthesis was found to be inconsistent and exceeded the pressure limit in microwave. To overcome the pressure problem, a base potassium tert-butoxide was added to dicyclopentadiene in diglyme and microwaved for 10 in @ 185oC to obtain cyclopentadienyl anion. This anion was added to a solution FeCl2.4H2O in DMSO and ferrocene was obtained in 5 minutes with a yield of 86%. To further
Chem 347/447
“Microwave synthesis of benchmark Organo-iron complexes” is an interesting article by Sean M. Garringer , Andrew J. Hesse , John R. Magers , Kristopher R. Pugh , Stacy A. O’Reilly and Anne M. Wilson which describes microwave- assisted technique in chemical synthesis. The authors detail the formation of various organo-iron species with the aid of a microwave. Using microwaves in chemical synthesis has resulted in not only decreased reaction time as well as maintained or improved yields when compared to traditional methods. Synthesis of organometallic compounds usually requires long time at elevated temperatures and these reaction conditions are optimal to exploit microwave assisted synthesis. The target compounds are the three classes of Organo-iron complexes which are sandwich complexes, cyclopentadienyl carbonyl complexes and phosphine tricarbonyl complexes. Several compounds from these classes were studied and it was found that refluxing time was reduced to few minutes from several hours, improving yields of some poor yielding compounds. The article describes in detail six schemes or synthesis of six different complexes using microwave and how it differed from the traditional synthetic method. In the Scheme 1 ferrocene was synthesized. Traditional way required reaction conditions of 175oC for 45 min and had 20% yields, whereas the first trial of microwave synthesis or one-pot synthesis had a yield of 40-70%. However, this synthesis was found to be inconsistent and exceeded the pressure limit in microwave. To overcome the pressure problem, a base potassium tert-butoxide was added to dicyclopentadiene in diglyme and microwaved for 10 in @ 185oC to obtain cyclopentadienyl anion. This anion was added to a solution FeCl2.4H2O in DMSO and ferrocene was obtained in 5 minutes with a yield of 86%. To further