Asymmetric Epoxidation Of Dihydronaphthalene With A Synthesized Jacobs :: essays research papers

Asymmetric Epoxidation of Dihydronaphthalene with a Synthesized JacobsensCatalystAbstract. 1,2 diaminocyclohexane was reacted with L-(+)-tartaric corrosive to yield(R,R)-1,2-diaminocyclohexane mono-(+)-tartrate season. The tartrate salt was hencereacted with potassium carbonate and 3,5-di-tert-butylsalicylaldehyde to yield(R,R)-N,N-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine, which wasthen reacted with Mn(OAc)2*4H2O and LiCl to form Jacobsens gas pedal. Thesynthesized Jacobsens catalyst was used to catalyze the epoxidation ofdihydronaphthalene. The products of this reaction were isolated, and it wasfound that the product yielded 1,2- pastedihydronaphthalene as advantageously asnaphthalene.IntroductionIn 1990, professor E.N. Jacobsen reported that chiral manganesecomplexes had the might to catalyze the asymmetric epoxidation ofunfunctionalized alkenes, providing enantiomeric excesses that regularlyreaching 90% and sometimes stupendous 98% . The chiral manganese c omplexJacobsen utilized was (R,R)-N,N-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminato-(2-)-manganese (III) chloride (Jacobsens Catalyst).(R,R) Jacobsens Catalyst Jacobsens catalyst opens up short pathways toenantiomerically pure pharmacological and industrial products via thesynthetically versatile epoxy function .In this paper, a synthesis of Jacobsens catalyst is performed (Scheme1). The synthesized catalyst is then reacted with an unfunctional alkene(dihydronaphthalene) to form an epoxide that is highly enantiomerically enriched,as well as an oxidized byproduct.Jacobsens work is important because it presents both a reagent and a rule to selectively guide an enantiomeric catalytic reaction of industrialand pharmacological importance. actually few reagents, let alone methods, areknown to be capable to perform such a function, which indicates the trulygroundbreaking importance of Jacobsens work.data-based SectionGeneral Protocol. 99% L-(+)- Tartaric Acid, ethanol,dihydr onaphthalene and glacial acetic acid were obtained from the AldrichChemical Company. 1,2 diaminocyclohexane (98% mix of cis/trans isomers) andheptane were obtained from the Acros Chemical Company. Dichloromethane andpotassium carbonate were obtained from the EM Science division of EM Industries,Inc. Manganese acetate was obtained from the Matheson, Coleman and BellManufacturing Chemists. atomic number 3 chloride was obtained form the JT BakerChemical Co. Refluxes were carried out development a cytosine V heating mantle (Glas-ColApparatus Co. 100 mL, 90 V) and cxxx V Variac (General Radio Company). Vacuumfiltrations were performed using a Cole Parmer operator Co. Model 7049-00aspirator pump with a Bchner funnel. For Thin Layer Chromatography (TLC)analysis, precoated Kodak chromatogram sheets (silica change 13181 withfluorescent indicator) were used in an ethyl acetate/hexane (14) eluent.TLCs were visualized using a UVP Inc. Model UVG-11 Mineralight Lamp (Short-waveUV-254 nm, 15 V , 60 Hz, 0.16 A). Masses were taken on a Mettler AE 100. Rotaryevaporations were performed on a Bchi Rotovapor-R. break up points weredetermined using a Mel-Temp (Laboratory Devices, USA) equipped with a Fluke 51digital thermometer (John Fluke Manufacturing Company, Inc.). Optical rotations(aD) were measured on a Dr. Steeg and tenant 6mbH, Engel/VTG 10 polarimeter.