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22halide into an excess of magnesium. Another problem with handling alkenylichalides is that they are lachrymators and skin irritants. A good fume hood isneeded when handling these reagents. As with other organometallic reactions, theTHF solvent must be thoroughly dried, by distilling over Na metal andbenzophenone.One key disadvantage to the Grignard reagent synthetic route in the CRSpheromone synthesis is the non-selectivity of the Grignard reagent in attackingelectrophilic carbons. The <strong>final</strong> CRS pheromone structure has an acetatecomponent. A bulky protecting group is needed to prevent attack at the acylcarbon by the Grignard reagent. A smaller acetate group in the same place wouldnot effectively prevent the Grignard reagent from attacking the acyl carbon.Because of this fact, the starting material citronellol must be converted tocitronellyl pivalate. If another method could be used to add the butenylcomponent and open the epoxide ring as a Grignard reagent does, but has betterselectivity towards attacking the C 6 epoxide ring, instead of the acetate, thepivalate protecting group would not be needed. A step could be removed from thetotal synthesis scheme, saving both time and money.In 1984, Dr. Bruce Lipschutz of the University of California at SantaBarbara published a study in which higher order, mixed organocuprates(R 2 Cu(CN)Li 2 ) were allowed to react with epoxides to yield alcohols. 28,29 It washypothesized that perhaps these higher order cuprates could be used to replace theGrignard reagent utilized in the synthesis of CRS pheromone. The theorizedreaction is shown in Figure 16.Reaction of higher order cuprates with 6,7-epoxycitronellyl acetate wasstudied to see if this would be a viable synthetic route. Synthesis of the higher
23order cuprate from Cu(CN) and R-Li was also studied. 30studied starting with an allylic halide with lithium metal. 31Synthesis of R-Li wasOButenyl 2Cu(CN)Li 2+OOOOOHFigure 16. Ring opening of epoxide using Higher Order Cuprates
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 36 and 37: RESULTS AND DISCUSSIONSynthesis of
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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