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RESULTS AND DISCUSSIONSynthesis of (3S) Citronellyl PivalateSynthesis of this compound was necessary to provide the starting materialfor the epoxidation reactions to follow. (3S) Citronellol is a good choice ofstarting material as it contains many features in the carbon skeleton of theCalifornia Red Scale pheromone. (3S) Citronellol already has a C 3 chiral carbonthat can be commercially obtained in high optical purity. Citronellol was reactedwith trimethylacetyl chloride to yield Citronellyl pivalate. The desired productwas primarily characterized by Infrared spectroscopy (IR), showing a strongabsorption band at 1729.24 cm -1 , characteristic of a carbonyl group present, wherethere was none in citronellol (Figure 17). The NMR spectrum showed a tripletpeak at 4.10 ppm, characteristic of an ester group created by acylation ofcitronellol (Figure 18). The yield of this reaction is good at 90%.Synthesis of (3S,6RS)-6,7-Epoxycitronellyl PivalateThe synthesis of this mixture of diastereomers was necessary in order tocharacterize the single diastereomer synthesized by using Jacobsen’s catalyst.Citronellyl pivalate was then epoxidized with m-chloroperoxybenzoic acid to givea mixture of diastereomers. Characterization of the epoxide mixture ofdiastereomers was done primarily by GC/MS (Figure 19, 20, 21). The progress ofthe reaction was monitored by disappearance of peaks due to starting material andappearance peaks due to product on the GC trace. Product characterization wasdone by 1 H NMR (Figure 22). A peak at 2.65 ppm (triplet) showed that theepoxide had formed, while disappearance of the alkene triplet at 5.10 ppm in thestarting
material showed that the alkene was gone. (Figure 23) Product also identified by25Figure 17. IR spectrum of (3S) citronellyl pivalate taken as neat sample
Page 1: ABSTRACTASYMMETRIC SYNTHESIS OF 6,7
Page 4 and 5: NOTE:THIS PAGE IS OPTIONAL, AND REQ
Page 6 and 7: APPROVEDFor the Department of Chemi
Page 8 and 9: ACKNOWLEDGMENTSI would like to than
Page 10 and 11: FigureLIST OF FIGURESPage1. Califor
Page 12 and 13: 37.38.39.ix13 C NMR Spectrum of (3S
Page 14 and 15: 2support the contention that the fe
Page 16 and 17: Figure 2. California Red Scale pher
Page 18 and 19: 6creation of the chiral center at C
Page 20 and 21: 8During the early 1990s Professor E
Page 22 and 23: 10across the top of the molecule, a
Page 24 and 25: 12molecule and also shows that the
Page 26 and 27: 14Figure 10. (R,R) Jacobsen’s cat
Page 28 and 29: 16stereoselectivity. With tri-subst
Page 30 and 31: 18physical properties (except optic
Page 32 and 33: 20Calo in 1990 published a method o
Page 34 and 35: 22halide into an excess of magnesiu
Page 38 and 39: Figure 18. 1 H NMR spectrum of (3S)
Page 40 and 41: Figure 20. GC/MS trace of (3S) citr
Page 42 and 43: Figure 22. 1 H NMR spectrum of (3S,
Page 44 and 45: 32IR spectroscopy .Separation of Ep
Page 46 and 47: Figure 25. GC/MS trace of (3S,6RS)-
Page 52 and 53: 40due to the starting material (3S)
Page 54 and 55: 42Figure 33. 1 H NMR spectrum of (3
Page 56 and 57: Figure 36. 13 C NMR spectrum of (3S
Page 58 and 59: 46Figure 37. 13 C NMR Spectrum of (
Page 60 and 61: 48major peak by GC/MS (Figure 40).
Page 62 and 63: Figure 42. Results of GC/MS library
Page 64 and 65: 52GC/MS trace showed that only inte
Page 66 and 67: EXPERIMENTALAll 1 H Nuclear Magneti
Page 68 and 69: 56Synthesis of (3S,6RS)-6,7-Epoxyci
Page 70 and 71: 58catalyst in the product. Another
Page 72 and 73: 60was observed and no temperature c
Page 74 and 75: REFERENCES1. Bodenheimer, F.S. Citr

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