Monthly Archives: January 2009
The Hydrolytic Kinetic Resolution – Jacobsen’s Catalyst
An Introduction Enantiomerically pure epoxides are extremely valuablechemical compounds due to controllable but high reactivity ofepoxides coupled with the vast array of reactions they canundergo with retention of stereochemical integrity. One canenvision a number of direct routes to asymmetric epoxides(Figure … Continue reading
Stains for TLC
Although the recipes can be found on internet, here are some I used in the lab. Ceric Ammonium Molybdate (CAM): This stain is prepared by dissolving 2.5 g of (NH4) 6-Mo7O24 and 1.0 g Ce(SO4)2 in 90 mL of water … Continue reading
Sulfur containing quaternary carbon center
How to build a S-containing quaternary carbon centerlike this: ways I can find out:1. enolate attack a S-nucleophile. ex. MeSSMe.2. 3,3-sigmatropic rearrangement.3. thioketone attacked by a Nu-.4. thiol 1,4-addition.5. thionium ions (ex. from thiolketal) attacked by a Nucleophile.6. methoxyphenylthiomethyllithium addition … Continue reading
Some pdf from group of Professor Scott Denmark
very good presentations, very broad topics. http://www.scs.uiuc.edu/denmark/presentations/ List of 2008: Transition Metal‐Catalyzed Carbon‐Carbon Bond Cleavage (C‐C Activation) The Petasis-Ferrier Union/Rearrangement Interrupted Nazarov Cyclizations Nickel Catalyzed sp3-sp3 Couplings Rhodium Catalyzed [5+2] Cycloaddition The 5 W’s of Chiral Dienes as Ligands for … Continue reading
benzylidene acetal of glucopyranoside
formation:1. bnezaldehyde -ZnCl22. benzaldehyde dimethyl acetal 3 eq.- TsOH 0.1 eq. in MeCN, refluxing. 2hr.works great. >60% yield.workup procedure:remove mecn to about half invacuo, then NaHCO3 aq. solution added to quench TsOH. Further remove meCN completely invacuo.EtOAc used to dissolve … Continue reading
Titrating n-buLi,s-buli, t-buli
method 1: Take a briquette of menthol (usually about 80-100 mg), dissolve that in dry THF (~2 mL) and then add 1-2 mg (you don’t need to really weight it) of triphenylmethane. You can roughly calculate how much of your … Continue reading
preparation of Methyl triphenyl Phosphonium Acetate
the correspongind phosphonium bromide 1 eq.dissolve in DCM. (0.5 M)NaOH 2 eq. dissolve in water. 1 M.then put the two solutions together in a separatory funnel, shake vigorously for 10 min at rt.then organic layer separated. washed with nahco3, brine.concentrated … Continue reading
petasis reagent cp2TiMe2
titanocene dichloride 1 eq.meli 2 eq. (can use excess)-5 C, meli in Et2O was added dropwise into titanocene dichloride in toluene (0.1-0.2 M) during 10 min.upon addition, red insoluable TiCP2Cl2 disappeared slowly.an intermediate TiCp2ClMe is soluable and red colored.the product … Continue reading
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