Journal of Chemical Ecology, Vol. 13, No. 1, 1987
STEREOSPECIFIC SYNTHESIS OF (Z,Z)-3,5TETRADECADIENOIC ACID, A COMPONENT OF Attagenus elongatulus (CASEY) PHEROMONE
W.J. DE J A R L A I S and E.A. E M K E N Northern Regional Research Center Agricultural Research Service U.S. Department of Agriculture Peoria, Illinois 61604
(Received October 16, 1985; accepted February 10, 1986) Abstract--A simple stereospecific synthesis of (Z,Z)-3,5-tetradecadienoic acid is described based upon coupling of 1-decyne and 3-butyn-l-ol to give 3,5-tetradecadiyn-1-ol. Subsequent reduction of the diyne to (Z,Z)-3,5-tetradecadien-l-ol and oxidation of the dienol gave the desired acid. Attagenus elongatulus were strongly attracted to the pure acid. Key Words--Coleoptera, Dermestidae, Attagenus elongatulus, (Z,Z)-3,5tetradecadienoic acid, Pheromone.
INTRODUCTION A major component of the sex pheromone of the dermestid beetle Attagenus elongatulus (Casey) was identified as (Z,Z)-3,5-tetradecadienoic acid (Fukui et al., 1977). The synthesis of this acid has been reported (Silverstein et al., 1967; Rodin et al., 1970) by m e t h o d s which depended upon gas chromatographic separation of geometrical isomers. Here we report a simplified, stereospecific synthesis of (Z,Z)-3,5-tetradecadienoic acid.
METHODS AND MATERIALS 1-Decyne and 3-butyn-1-ol were purchased (Farchan Div., Albany International).
179 0098-0331/87/0100-0179505.00/0
9 1987 Plenum Publishing Corporation
180
DE JARLAIS AND EMKEN
1-Bromo-l-decyne was prepared by a reported method for a homolog (Brandsma, 1971) in 88% yield, bp 55-57~ torr, pure by GC (EGSS-X). [13C]NMR (delta values-assigned carbon): 14.03-C10, 19.75-C3, 22.08-C9, 31.80-C8, 37.43-C1, 80.52-C2. 3,5-Tetradecadiyn-l-ol was prepared as described by Brandsma (1971) for a homolog in 88 % yield following low-temperature crystallization from pentane-hexane, 98% pure by GC (EGSS-X). [13C]NMR: 14.03-C14, 19.17-C7, 22.68-C13, 23.72-C2, 31.84-C12, 60.96-C1, 65.05, 67.32, 73.69, 78.44C3-6. (Z,Z)-3,5-Tetradecadien-l-ol was prepared by reduction of the above diynol with dicyclohexylborane as described for reduction of a similar diynol (Svirskaya et al., 1980; see also Zweifel and Polston, 1970) in 82% yield, bp 112-114~ torr, pure by GC (EGSS-X and 007-CPS-2 50 m capillary, Quadrex Corp.). [13C]NMR: 14.10-C14, 22.74-C13, 27.62-C7, 31.19-C2, 31.97C12, 62.39-C1, 123.35. 126.66, 126.86, 133.48-C3-6. (Z,Z)-3,5-Tetradecadienoic acid was prepared by oxidation of the alcohol with Jones reagent (Djerassi, 1956), i.e., 2.67 M CrO 3 in H2SO 4. A number of experiments was carried out to determine suitable conditions. A typical experiment was as follows: To a solution of 2.0 g (9.52 mmol) of (Z,Z)-3,5-tetradecadien-l-ol in 200 ml acetone was added dropwise at 10-16~ 14.2 ml Jones reagent while stirring vigorously under N2. After 10 min, the mixture was poured into 500 ml ice and saline (saturated NaC1 solution). The product was extracted with ether and washed twice with saline. The ether solution was dried and, after filtration and evaporation, gave 1.76 g of yellow oil. The crude product was applied in approximately four equal portions to a column (4.7 x 45 cm) of 30/zm silica gel and eluted with 1% methanol in hexane. The eluate was monitored with a UV detector at 256 nm. The last eluted peaks from each run were combined to give 0.8 g of oil that was crystallized from hexane to give 0.11 g colorless crystals. GC of a methylated sample (diazomethane) on the 007-CPS-2 capillary showed only one peak. The filtrate was evaporated to yield 0.54 g of oil that was purified on a reversedphase C-18 column to separate 0.14 g (Z,Z)-3,5-tetradecadienoic acid. Nonanoic acid was identified as the main acid impurity by MW (MS) and comparison with the GC retention of an authentic sample of the methyl ester. GC of the methyl esters of the crude acid fraction also had trace amounts of two tetradecadienoate isomers. These isomers were separated on both the 007-CPS-2 and on a 30 m DB-1 (J & W Scientific) capillary that was coupled to a Finnegan mass spectrometer equipped for CI (chemical ionization) with isobutane. The structure of the (Z,Z)-3,5-tetradecadienoic acid was confirmed by [~3C]NMR: 177.7-C1; 134.8, 127.0, 122.6, 120.9-C3-6; 32.8-C2; 31.9-C12; 27.7-C7; 22.7-C13; 14.06-C14; and by MS-CI which gave MW 238.
SYNTHESISOF Z,Z-3,5-TETRADECADIENOICACID
181
RESULTS AND DISCUSSION
The syntheses scheme is outlined in Figure 1. The conversion of 1-decyne to 1-bromo-1-decyne was effected by Brandsma's (1971) procedure. The bromodecyne was coupled by Chodkiewitz reaction (Brandsma, 1971) to yield 3,5tetradecadiyn-l-ol. The alternative coupling of 1-decyne and 4-bromo-3-butyn1-ol gave only ca. 38% conversion in our hands. Our attempts to reduce 3,5-tetradecadiyn-l-ol by hydrogenation over Lindlar's catalyst (Lindlar and Dubuis, 1966) were unsatisfactory, giving a complex mixture of products. Chemical reduction using dicyclohexylborane gave smooth conversion of 3,5-tetradecadiyn- 1-ol to (Z,Z)-3,5-tetradecadien- 1-ol (Svirskaya et al., 1980). Oxidation of (Z,Z)-3,5-tetradecadien-l-ol to the corresponding acid was carried out in moderate yield with the Jones reagent (Djerassi, 1956). Oxidation of an alcohol to the corresponding acid with chromic acid has been plagued by oxidation of the in situ-formed hemiacetal to ester (Craig and Homing, 1960) so that yields in the 20-50% range are obtained (Holland and Gilman, 1974). Holland and Gilman reported an improved procedure involving reversed addition, i.e., slow addition of the alcohol to the chromic acid solution, and were able to reduce the yield of ester substantially. In our hands this method gave good results with a model compound but poorer results than we obtained with the normal addition procedure with tetradecadienol as substrate, probably due I) n-C4H9Li CH3(CH2)7C~CH
> CH3(CH2)7C~CBr 2) Br 2 yield
HC~C(CH2)20H Chodkiewitz
>
CH3(CH2)7C~C-C~C(CH2)20H
yield (C6Hll)2BH
>
88%
88%
CH~ (CH~) .C=C-C=C (CH.) ~OH
Z/HHHH yield
zz 82%
Cr03> CH3
(CHg)~C=CC=CCH~CO.H - /H HH H z z yield
35%
FIG. 1. Scheme for synthesis of (Z,Z)-3,5-tetradecadienoic acid.
182
DE JARLAISAND EMKEN
E_ Lr
rr"
I I I 250 750 1250 1750 Eluate Volume, ml. FIG. 2. Separation of acid fraction on 45 • 4.7-cm silica column. Eluent: 12 ml/min of 1% methanol in hexane. Detector: UV, 265 nm, and 2 AUFS. Sample: 305 mg of oxidized (Z,Z)-3,5-tetradecadien-l-ol. The acid fraction comprised eluate volume from 750 to 1500 ml.
to over oxidation. The Holland and Gilman method subjects the oxidation products to prolonged contact with excess oxidant. Rodin et al. (1970) reported oxidation o f (Z)-5-tetradecen-3-yn-l-ol with chromic acid o f unspecified strength [reference is made to Fieser and Fieser (1967), but several different chromic acid compositions are mentioned on the cited page including that which we used]. A yield o f 67 % was reported, but no
SYNTHESIS OF
Z,Z-3,5-TETRADECADIENOICACID
183
purity was specified. A subsequent purification was effected by preparative GC to furnish a purified methyl ester in unspecified yield. Pyridinium dichromate (Corey and Schmidt, 1979) oxidation of the tetradecadienol gave substantial amounts of c~,/3-unsaturated acids. Similar results were obtained when a stepwise approach was tried by oxidation of the dienol to aldehyde with dipyridine chromic anhydride complex (Valicenti and Holman, 1976). The aldehyde contained much c~,/3-unsaturation. Phase transfer oxidation of alcohols to aldehydes and ketones has been described (Pletcher and Tait, 1978; Landini et al., 1979; Brown et al., 1971). The method of Brown does not require a phase transfer agent, but was applied only to secondary alcohols. We investigated a similar procedure to Brown's for the oxidation of 1-octanol in ether. The product mixture contained 1-octanol, octanal, octyl octanoate, octanoic acid and probably octanal trimer, but all of these were resolvable on a 10-fl Carbowax MTPA glass GC column so that oxidation could conveniently be followed by GC. A simple procedure of shaking 5 rain while cooling with tap water an ether solution (25 or 250 ml) of 10 mmol 1-octanol with 0.5, 1, or 2 equivalents of Jones reagent (an equivalent = oxidation to acid) was followed. This procedure with two equivalents of oxidant at the higher dilution gave an 80 % yield of octanoic acid and only 12 % of octyl octanoate or about the same yields as reported by Gilman and Holland. When this procedure was applied to oxidation of the dienol, we obtained a 61% yield of crude acids, of which 24 % was at the desired acid retention (GC of methyl esters) and 36 % had retention equivalent to methyl nonanoate. The best result in the oxidation of the dienol to (Z,Z)-3,5-tetradecadienoic acid was obtained using a 200 % excess of the Jones reagent, whereby 71% of the product weight was estimated to be in the acid fraction. The acid fraction consisted principally of the desired dienoic acid (ca. 53 %) and nonanoic acid (ca. 35 %) (Fig. 2). Trace amounts of isomeric dienoic acids were also present as established by capillary GC-MS-CI. The (Z,Z)-3,5-dienoic acid was separated by reversed-phase chromatography or by crystallization. Absence of isomers in the purified acid was established by capillary GC (007-CPS-2). Test showed (Z,Z)-3,5-tetradecadienoic acid attractive to Attagenus elongatulus (Burkholder, personal communication). REFERENCES L. 1971. Preparative Acetylene Chemistry. American Elsevier, New York, p. 98 (1-bromo alkyne), p. 169 (Chodkiewitz). BROWN,H.C., GARG,C.P., and LIU,K.-T. 1971. The oxidation of secondary alcohols in diethyl ether with aqueous chromic acid. A convenient procedure for the preparation of ketones in high epimericpurity. J. Org. Chem. 31:387-390. COREY, E.J., and SCHMIDT,G, 1979. Useful procedures for the oxidation of alcohols involving pyridinium dichromate in aprotic media. TetrahedronLett. 5:399-402. BRANDSMA,
184
DE JARLAIS AND EMKEN
CRAIG, J.C., and HORNING,E.C. 1960. Preparation of esters by hemiacetal oxidation. J. Org. Chem. 25:2098-2102. DJERASSI, C., ENGLE, R.R., and BOWERS, A. 1956. The direct conversion of steroidal A5-3/3alcohols to A5 and A4-3-ketones. J. Org. Chem. 21:1547-1549. FIESER, L.F., and FIESER, M. 1967. Reagents for Organic Synthesis, Vol. 1. John Wiley & Sons, New York, p. 142. FUKUI, H., MATSUMURA,F., BARAK, A.V., and BURKHOLDER,W.E. 1977. Isolation and identification of a major sex-attracting component of Attagenus elongatulus (Casey) (Coleoptera: Dermestidae). J. Chem. Ecol. 3:539-548. HOLLAND, B.C., and GILMAN, N.W. 1974. An improved procedure for the oxidation of alkynols to alkynoic acids. Synth. Commun. 4:203-210. LANDINI, D., MONTANARI, F., and ROLLA, F. 1979. Selective oxidation of primary alcohols to aldehydes under phase-transfer conditions. Synthesis 134-136. LINDLAR, H., and DtJBuIS, R. 1966. Palladium catalyst for partial reduction of acetylenes. Org. Synth. 46:89-92. PLETCHER, D., and TAIT, S.J.D. 1978. A procedure for the oxidation of alcohols of aldehydes based on phase transfer catalysts. Tetrahedron Lett. 19:1601-1602. RODIN, J.O., LEAFFER, M.A., and SILVERSTEIN,R.M. 1970. Synthesis of trans-3,cis-5-tetradecadienoic acid (megatomoic acid), the sex attractant of the black carpet beetle, and its geometric isomers. J. Org. Chem. 35:3152-3154. SILVERSTEIN,R.M., RODIN, J.O., BURKHOLDER,W.E., and GORMAN,J.E. 1967. Sex attractant of the black carpet beetle. Science 157: 85-87. SVIRSKAYA,P.I., LEZNOFF, C.C., and ROELOFS, W.L. 1980. A steroselective synthesis of a cis,cis conjugated dienol, A candidate pheromone. Synth. Commun. 10:391-397. VALICENTI, A.J., and HOLMAN, R.T. 1976. Oxidation of long-chain alcohols to aldehydes by the dipyridine chromic anhydride complex. Chem. Phys. Lipids 17:389-392. ZWEIFEL, G., and POLSTON, N.L. 1970. Selective hydroboration of conjugated diynes with dialkylboranes. A convenient route to conjugated cis-enynes, o:,/3-acetylenic ketones, and cis,cisdienes. J. Am. Chem. Soc. 92:4068-4071.
STEREOSPECIFIC SYNTHESIS OF (Z,Z)-3,5TETRADECADIENOIC ACID, A COMPONENT OF Attagenus elongatulus (CASEY) PHEROMONE
W.J. DE J A R L A I S and E.A. E M K E N Northern Regional Research Center Agricultural Research Service U.S. Department of Agriculture Peoria, Illinois 61604
(Received October 16, 1985; accepted February 10, 1986) Abstract--A simple stereospecific synthesis of (Z,Z)-3,5-tetradecadienoic acid is described based upon coupling of 1-decyne and 3-butyn-l-ol to give 3,5-tetradecadiyn-1-ol. Subsequent reduction of the diyne to (Z,Z)-3,5-tetradecadien-l-ol and oxidation of the dienol gave the desired acid. Attagenus elongatulus were strongly attracted to the pure acid. Key Words--Coleoptera, Dermestidae, Attagenus elongatulus, (Z,Z)-3,5tetradecadienoic acid, Pheromone.
INTRODUCTION A major component of the sex pheromone of the dermestid beetle Attagenus elongatulus (Casey) was identified as (Z,Z)-3,5-tetradecadienoic acid (Fukui et al., 1977). The synthesis of this acid has been reported (Silverstein et al., 1967; Rodin et al., 1970) by m e t h o d s which depended upon gas chromatographic separation of geometrical isomers. Here we report a simplified, stereospecific synthesis of (Z,Z)-3,5-tetradecadienoic acid.
METHODS AND MATERIALS 1-Decyne and 3-butyn-1-ol were purchased (Farchan Div., Albany International).
179 0098-0331/87/0100-0179505.00/0
9 1987 Plenum Publishing Corporation
180
DE JARLAIS AND EMKEN
1-Bromo-l-decyne was prepared by a reported method for a homolog (Brandsma, 1971) in 88% yield, bp 55-57~ torr, pure by GC (EGSS-X). [13C]NMR (delta values-assigned carbon): 14.03-C10, 19.75-C3, 22.08-C9, 31.80-C8, 37.43-C1, 80.52-C2. 3,5-Tetradecadiyn-l-ol was prepared as described by Brandsma (1971) for a homolog in 88 % yield following low-temperature crystallization from pentane-hexane, 98% pure by GC (EGSS-X). [13C]NMR: 14.03-C14, 19.17-C7, 22.68-C13, 23.72-C2, 31.84-C12, 60.96-C1, 65.05, 67.32, 73.69, 78.44C3-6. (Z,Z)-3,5-Tetradecadien-l-ol was prepared by reduction of the above diynol with dicyclohexylborane as described for reduction of a similar diynol (Svirskaya et al., 1980; see also Zweifel and Polston, 1970) in 82% yield, bp 112-114~ torr, pure by GC (EGSS-X and 007-CPS-2 50 m capillary, Quadrex Corp.). [13C]NMR: 14.10-C14, 22.74-C13, 27.62-C7, 31.19-C2, 31.97C12, 62.39-C1, 123.35. 126.66, 126.86, 133.48-C3-6. (Z,Z)-3,5-Tetradecadienoic acid was prepared by oxidation of the alcohol with Jones reagent (Djerassi, 1956), i.e., 2.67 M CrO 3 in H2SO 4. A number of experiments was carried out to determine suitable conditions. A typical experiment was as follows: To a solution of 2.0 g (9.52 mmol) of (Z,Z)-3,5-tetradecadien-l-ol in 200 ml acetone was added dropwise at 10-16~ 14.2 ml Jones reagent while stirring vigorously under N2. After 10 min, the mixture was poured into 500 ml ice and saline (saturated NaC1 solution). The product was extracted with ether and washed twice with saline. The ether solution was dried and, after filtration and evaporation, gave 1.76 g of yellow oil. The crude product was applied in approximately four equal portions to a column (4.7 x 45 cm) of 30/zm silica gel and eluted with 1% methanol in hexane. The eluate was monitored with a UV detector at 256 nm. The last eluted peaks from each run were combined to give 0.8 g of oil that was crystallized from hexane to give 0.11 g colorless crystals. GC of a methylated sample (diazomethane) on the 007-CPS-2 capillary showed only one peak. The filtrate was evaporated to yield 0.54 g of oil that was purified on a reversedphase C-18 column to separate 0.14 g (Z,Z)-3,5-tetradecadienoic acid. Nonanoic acid was identified as the main acid impurity by MW (MS) and comparison with the GC retention of an authentic sample of the methyl ester. GC of the methyl esters of the crude acid fraction also had trace amounts of two tetradecadienoate isomers. These isomers were separated on both the 007-CPS-2 and on a 30 m DB-1 (J & W Scientific) capillary that was coupled to a Finnegan mass spectrometer equipped for CI (chemical ionization) with isobutane. The structure of the (Z,Z)-3,5-tetradecadienoic acid was confirmed by [~3C]NMR: 177.7-C1; 134.8, 127.0, 122.6, 120.9-C3-6; 32.8-C2; 31.9-C12; 27.7-C7; 22.7-C13; 14.06-C14; and by MS-CI which gave MW 238.
SYNTHESISOF Z,Z-3,5-TETRADECADIENOICACID
181
RESULTS AND DISCUSSION
The syntheses scheme is outlined in Figure 1. The conversion of 1-decyne to 1-bromo-1-decyne was effected by Brandsma's (1971) procedure. The bromodecyne was coupled by Chodkiewitz reaction (Brandsma, 1971) to yield 3,5tetradecadiyn-l-ol. The alternative coupling of 1-decyne and 4-bromo-3-butyn1-ol gave only ca. 38% conversion in our hands. Our attempts to reduce 3,5-tetradecadiyn-l-ol by hydrogenation over Lindlar's catalyst (Lindlar and Dubuis, 1966) were unsatisfactory, giving a complex mixture of products. Chemical reduction using dicyclohexylborane gave smooth conversion of 3,5-tetradecadiyn- 1-ol to (Z,Z)-3,5-tetradecadien- 1-ol (Svirskaya et al., 1980). Oxidation of (Z,Z)-3,5-tetradecadien-l-ol to the corresponding acid was carried out in moderate yield with the Jones reagent (Djerassi, 1956). Oxidation of an alcohol to the corresponding acid with chromic acid has been plagued by oxidation of the in situ-formed hemiacetal to ester (Craig and Homing, 1960) so that yields in the 20-50% range are obtained (Holland and Gilman, 1974). Holland and Gilman reported an improved procedure involving reversed addition, i.e., slow addition of the alcohol to the chromic acid solution, and were able to reduce the yield of ester substantially. In our hands this method gave good results with a model compound but poorer results than we obtained with the normal addition procedure with tetradecadienol as substrate, probably due I) n-C4H9Li CH3(CH2)7C~CH
> CH3(CH2)7C~CBr 2) Br 2 yield
HC~C(CH2)20H Chodkiewitz
>
CH3(CH2)7C~C-C~C(CH2)20H
yield (C6Hll)2BH
>
88%
88%
CH~ (CH~) .C=C-C=C (CH.) ~OH
Z/HHHH yield
zz 82%
Cr03> CH3
(CHg)~C=CC=CCH~CO.H - /H HH H z z yield
35%
FIG. 1. Scheme for synthesis of (Z,Z)-3,5-tetradecadienoic acid.
182
DE JARLAISAND EMKEN
E_ Lr
rr"
I I I 250 750 1250 1750 Eluate Volume, ml. FIG. 2. Separation of acid fraction on 45 • 4.7-cm silica column. Eluent: 12 ml/min of 1% methanol in hexane. Detector: UV, 265 nm, and 2 AUFS. Sample: 305 mg of oxidized (Z,Z)-3,5-tetradecadien-l-ol. The acid fraction comprised eluate volume from 750 to 1500 ml.
to over oxidation. The Holland and Gilman method subjects the oxidation products to prolonged contact with excess oxidant. Rodin et al. (1970) reported oxidation o f (Z)-5-tetradecen-3-yn-l-ol with chromic acid o f unspecified strength [reference is made to Fieser and Fieser (1967), but several different chromic acid compositions are mentioned on the cited page including that which we used]. A yield o f 67 % was reported, but no
SYNTHESIS OF
Z,Z-3,5-TETRADECADIENOICACID
183
purity was specified. A subsequent purification was effected by preparative GC to furnish a purified methyl ester in unspecified yield. Pyridinium dichromate (Corey and Schmidt, 1979) oxidation of the tetradecadienol gave substantial amounts of c~,/3-unsaturated acids. Similar results were obtained when a stepwise approach was tried by oxidation of the dienol to aldehyde with dipyridine chromic anhydride complex (Valicenti and Holman, 1976). The aldehyde contained much c~,/3-unsaturation. Phase transfer oxidation of alcohols to aldehydes and ketones has been described (Pletcher and Tait, 1978; Landini et al., 1979; Brown et al., 1971). The method of Brown does not require a phase transfer agent, but was applied only to secondary alcohols. We investigated a similar procedure to Brown's for the oxidation of 1-octanol in ether. The product mixture contained 1-octanol, octanal, octyl octanoate, octanoic acid and probably octanal trimer, but all of these were resolvable on a 10-fl Carbowax MTPA glass GC column so that oxidation could conveniently be followed by GC. A simple procedure of shaking 5 rain while cooling with tap water an ether solution (25 or 250 ml) of 10 mmol 1-octanol with 0.5, 1, or 2 equivalents of Jones reagent (an equivalent = oxidation to acid) was followed. This procedure with two equivalents of oxidant at the higher dilution gave an 80 % yield of octanoic acid and only 12 % of octyl octanoate or about the same yields as reported by Gilman and Holland. When this procedure was applied to oxidation of the dienol, we obtained a 61% yield of crude acids, of which 24 % was at the desired acid retention (GC of methyl esters) and 36 % had retention equivalent to methyl nonanoate. The best result in the oxidation of the dienol to (Z,Z)-3,5-tetradecadienoic acid was obtained using a 200 % excess of the Jones reagent, whereby 71% of the product weight was estimated to be in the acid fraction. The acid fraction consisted principally of the desired dienoic acid (ca. 53 %) and nonanoic acid (ca. 35 %) (Fig. 2). Trace amounts of isomeric dienoic acids were also present as established by capillary GC-MS-CI. The (Z,Z)-3,5-dienoic acid was separated by reversed-phase chromatography or by crystallization. Absence of isomers in the purified acid was established by capillary GC (007-CPS-2). Test showed (Z,Z)-3,5-tetradecadienoic acid attractive to Attagenus elongatulus (Burkholder, personal communication). REFERENCES L. 1971. Preparative Acetylene Chemistry. American Elsevier, New York, p. 98 (1-bromo alkyne), p. 169 (Chodkiewitz). BROWN,H.C., GARG,C.P., and LIU,K.-T. 1971. The oxidation of secondary alcohols in diethyl ether with aqueous chromic acid. A convenient procedure for the preparation of ketones in high epimericpurity. J. Org. Chem. 31:387-390. COREY, E.J., and SCHMIDT,G, 1979. Useful procedures for the oxidation of alcohols involving pyridinium dichromate in aprotic media. TetrahedronLett. 5:399-402. BRANDSMA,
184
DE JARLAIS AND EMKEN
CRAIG, J.C., and HORNING,E.C. 1960. Preparation of esters by hemiacetal oxidation. J. Org. Chem. 25:2098-2102. DJERASSI, C., ENGLE, R.R., and BOWERS, A. 1956. The direct conversion of steroidal A5-3/3alcohols to A5 and A4-3-ketones. J. Org. Chem. 21:1547-1549. FIESER, L.F., and FIESER, M. 1967. Reagents for Organic Synthesis, Vol. 1. John Wiley & Sons, New York, p. 142. FUKUI, H., MATSUMURA,F., BARAK, A.V., and BURKHOLDER,W.E. 1977. Isolation and identification of a major sex-attracting component of Attagenus elongatulus (Casey) (Coleoptera: Dermestidae). J. Chem. Ecol. 3:539-548. HOLLAND, B.C., and GILMAN, N.W. 1974. An improved procedure for the oxidation of alkynols to alkynoic acids. Synth. Commun. 4:203-210. LANDINI, D., MONTANARI, F., and ROLLA, F. 1979. Selective oxidation of primary alcohols to aldehydes under phase-transfer conditions. Synthesis 134-136. LINDLAR, H., and DtJBuIS, R. 1966. Palladium catalyst for partial reduction of acetylenes. Org. Synth. 46:89-92. PLETCHER, D., and TAIT, S.J.D. 1978. A procedure for the oxidation of alcohols of aldehydes based on phase transfer catalysts. Tetrahedron Lett. 19:1601-1602. RODIN, J.O., LEAFFER, M.A., and SILVERSTEIN,R.M. 1970. Synthesis of trans-3,cis-5-tetradecadienoic acid (megatomoic acid), the sex attractant of the black carpet beetle, and its geometric isomers. J. Org. Chem. 35:3152-3154. SILVERSTEIN,R.M., RODIN, J.O., BURKHOLDER,W.E., and GORMAN,J.E. 1967. Sex attractant of the black carpet beetle. Science 157: 85-87. SVIRSKAYA,P.I., LEZNOFF, C.C., and ROELOFS, W.L. 1980. A steroselective synthesis of a cis,cis conjugated dienol, A candidate pheromone. Synth. Commun. 10:391-397. VALICENTI, A.J., and HOLMAN, R.T. 1976. Oxidation of long-chain alcohols to aldehydes by the dipyridine chromic anhydride complex. Chem. Phys. Lipids 17:389-392. ZWEIFEL, G., and POLSTON, N.L. 1970. Selective hydroboration of conjugated diynes with dialkylboranes. A convenient route to conjugated cis-enynes, o:,/3-acetylenic ketones, and cis,cisdienes. J. Am. Chem. Soc. 92:4068-4071.
