Write rational arrow-pushing mechanisms leading to three additional products that might have been formed in the reaction of α-pinene oxide with aqueous sulfuric acid that are different from the product you isolated and the decomposition product you identified
When a student ran an asymmetric dihydroxylation reaction using cis-stilbene and the ligand (DHQ)2PHAL, the hydrobenzoin showed an optical rotation of 0°
Propose three different syntheses of the alcohol shown below starting with a ketone and a Grignard reagent. In all cases, first show how you would make the Grignard reagent
A student has a dirty syringe and rinses it with acetone just before using it to transfer the ether to the Grignard that has just been initiated. What compound will contaminate the product?
What product might you obtain from the experiment if you used hydrochloric acid in methanol to protonate the alkoxide? Write a rational arrow-pushing mechanism for the formation of this product
A common strategy used to distinguish the diastereomeric meso and racemic forms of 1,2-diaryl-1,2-ethanediols is to prepare the acetonides and then examine the 1 H and 13C[1 H] spectra of these compounds. An acetonide is a ketal derived from the reaction of a vicinal diol with acetone in the presence of an acid catalyst
Explain why the 1 H and 13C[1 H] NMR spectra of the meso and the racemic forms of 1,2-diphenyl-1,2-ethanediol are not informative in distinguishing these stereoisomers
If the racemic mixture of the hydrobenzoins were formed in the reaction of benzil with sodium borohydride, describe a set of experimental conditions for which you might get a non-racemic mixture of these two products. You can change anything except the two starting materials
The product from your reaction has a sharp melting point, indicating that it is either meso-hydrobenzoin or a racemic mixture of the (1R, 2R) and (1S, 2S) enantiomers. Why is it not possible that your product is either the (1R, 2R) or the (1S, 2S) pure enantiomer?
A student was in a hurry to leave the lab and recorded the melting point of the recrystallized trimyristin right after washing the crystals with cold acetone. The melting point range was 46–50°C. Is this a good result? If not, explain what happened
What probably occurred if, after the recrystallization of trimyristin, the crystals had black particles dispersed throughout? What could be done at this point to correct the situation?
Gas chromatographic analysis of the tert-butyl methyl ether collected from the distillation in Part II of Laboratory Period 1 showed no impurities in the distillate. The oil of nutmeg is known to consist of many other organic compounds besides trimyristin. What does the purity of the distillate indicate about these other compounds?
In Part III of Laboratory Period 1, after treating the crude extract with activated carbon, the solution was somewhat lighter in color, but still quite dark. Knowing that trimyristin is in fact a white crystalline compound, why wasn’t more activated carbon used in an attempt to remove most of the colored impurities?