有机化学 YOUJI HUAXUE,1999,19,184—189 研究简报 ,
、 j从4一戊烯醛经增碳反应合成5一己烯酸甲酯类化合物
陈立功* 李 阳、//孟 秫 李 渊 吕 萌 罗舍兵 王 勇
— — — ; 学化工学院应用化学与精细化工系 天津300072)
摘要 通过4,8,12一三甲基一4,8,12一三烯醛(1)类四戊烯醛衍生物的增一碳反应合成了5,9.13一三甲基一
5,9,13一十四三烯醛甲醑(3)及 5一己烯酿甲醑衍生物(7—9)。用甲氧基甲基三苯基膦处理4一戊烯醛类化合物生
成烯基醚,PCC氧化所生成的烯醚则得到标题化台物.5一己烯酿甲醑类化台物 。
关■词 反应, ,反式多烯酯,醛增一碳反应
.Witti~ PCCl~
茂坼醴
血
1
a
己
bo
薅
ut b
画嚏甲
iomim
两
etl c iz a
曾
tio
名
m polyeneIn cohcemod wi the P eet about bio cyelizatiorm of polyene aey ntermediates,the tll roi l i ,
phenylselenyl esters of all—trans polyene carboxylie aeids we chosen∞ the precur~m_IJ.One example
of synthetic strategy for selenyl e~ters is described in Scheme 1,
洲 业 一oH ——· 一O l_二,
Hg(OAc~,80%
、 ,M唧
⋯ .
一
PB ,Ph2S电
As shown in Scheme 1, 4,8,12一trimethyl— trans一4,8,12一t}Iirdec e【Ial can be easily
prepared from 2一methylpmpenol thro~,gh a series of cl ∞n rearrangements and gnS~ d reactions[
.
The left thing we need to deal with is one—carbon homologation of aldehydeB to esters.A number of
1997—11—10收稿,1998—07—08修回。
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第 2期 胨立功等 :从 4一戊烯醛经增碳反应合成 5一己烯酸甲醣类化合物 185
synthetic methods have become available for effecting aldehyde homologations
. However,the present
procedures reported here are typical example of one—carbon homologation of aldehydes to esters mediated
by combination of Wittig reaction and selective PCC oxidation.
The target molecule(3),(7—9)w唧 first synthesized by US in 1994[ .5一bexenates normally Call
be prepared by Wittig reaction of aldehydes,but the stereochemistry of the forming carbon—carbon
double bond norm ally is c/s.Otherwise,Claisen rearrangement inakes the forming double bond being
trai'~. The stereochemistry of all the double bo nds of required precursom for polyenecyelization
investigation must be tr~i't$,and the methyl substituents in the precursors must be at 5,9,13,17 position
because the stereochemistry of cyelization products and the eyclization mode would be influenced largely
by the stereechemistry of double bonds and substitution position.Th us,the above mentioned procedures
we∞ employed in the present project.
1 Rem lb and diseut~ions
As well known,pyfidinium ebforechromate(Pcc)has been found extensive use in organic synthesis
as oxidants for oxidation of alcohols to aldehydesL4i.In 1977 Piancatelli an d his coworkers reported an
nnu~ual selective oxidation of enol etheI吕to corresponding esters with pCCtSJ.With consideration that enol
ethers Pan be easily prepared from aldehydes an d W ittig reagentsL ,we studied preparation of trait8—5
— - pentenoic acid derivatives from trans—-4—-be tenal derivatives by Wittig reac tion and sdec tive PCC
oxidation.
we first examined reaction of4,8,12一trimethyl一抛m 一4,8,12一thidecatrienal(1)with methoxy
bromide.As expected,treatanent of aldehyde(1)with Wittig reagent
afforded a mixture of trar~一 and蕊 一enol ethers(2)in 68% yield.PCC oxidation ofthe mixture of
tran8一 and c/s—end ethers(2)produced the corresponding este~,methyl 5,9,13一trimethylbutadeca
一 5,9,13一trienoate(3)in 73% field.The mixture of trans— and cis—enol ethers(2)need not be
separated and oxidation is high selective,all of the trarts carbo n— carbon double bo nds and their
stereoehemistry maintained,nO~pimerizafion products were detected(described in Scheme 2).
1
MeOCH2PPh3Br
3
Scheme 2
2
Th e obtained results encouraged US next to exal3ftine preparations of uther eBt% with four irons
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186 有 机 化 学 1999在
carbon — carbon double bonds, such aS, methyl 5,9, 13 一 trimethyl 一 5,9, 13, 17 一
e(7),methyl 5,9,13,17一tetramethyl一1,5,9,13,17一oetadecapetoenoate(8)
methyl 17一phenyl一5,9,13一trimethyl一1,5,9,13,17一oetadecapetaenoate(9),according to the
8dtiue methodology.Their structures and obtained~ ults are shown in the Scheme 3.
Rl }L H,(.)75%
RI Me,R2-】 (5)70%
Rl=H'R2=P (6】69%
R1=H,R2=H,(7)75%
Rz Me,R2= (I)60%
R1 H,R2。n (9)68%
Scheme 3
As we known that the required all—traPd aldehydes are easily synthesized througIl a series of Claisen
唧 m 心 and嘶 reactions from simph aldehydes and bre~ des .Tl1e required Wittig reagent,
methoxymethyltrlpllenylphosphonium bromide js commercially available. e obtmnnd results indicate that
the Wittig reaction is effective and proceed in }Ii yield smoothly under mild reaction conditions to give
desired enol ethem.the isolarnd yields are between 68% 一75% .
The oxidation of the obtained enol ethem with PCC undergoes selectively and effectively to give
desired estem with 60% 一75% yin~d ander loom temperature.Tl1e overall yields are about 50% . e
mechanism for the W ittig reactions are we1l known.but the mechan _峙m for the PCC oxidafion of enol
ethers should be different from the mechanism for PCC 0xidatiO11 of alcohols. e PCC oxidatiOll
mechanism of enol ether wsB reported that the initial electmphilic attack upon the ulefm by the PCC to
afrord 81'1 unstable intermedlate which then undergoes heterolytie cleavage of the Cr— b0nd.
accompanied by a 1,2一hydride shift gave the es tem.tsl Therefore
, we propose that the PCC oxidation
mechanism of po lyenenol ethem is simihr an d described iU Sc heme 4.
+ [cro3c1]’C~[sNH+
Sc heme 正
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第 2期 陈立功等 :从 4一戊烯醛经增碳反应合成 5一己烯酸 甲酯类化合物 187
In summary,combination of Wittig reaction between methoxymethyltfiphenylphosphonium bromide
and aldebyder,and PCC oxidation of the cnol ethers provides a convenient methodology for one—carbon
homologation from aldehyder to corresponding ertcl~.The present methodology uses readily accessible
inexpensive reagents for effecting a useful transformation.Th e conditions generally mild and the yield
ofthe esters is good.thus.a novd one—carbon homologation method was established.
2 Experimental details
Infrared spectra we∞ recorded in a Perkin—Elmer 1600 series spectrometer.Unlea.,s stated otherwise
solutionin deuteriachloroform w丑sus ed forthe deterraination ofNMR spectra.
I—methox~一5,9,13一trhnethyibutadeca一1,5,9,13一“吐ra蚰e(2)Lithium his(trimetbylsily1)
amide(15.8 mL,15.8 anno1)was added dropwlse to a solution of methoxymethyltriphenylphosphonium
chloride(5.6g,15.8 mmo1)in THF(35 mL)under nitrogen at 0℃.After the mixture was stilted
1h,4,8,12一trimethyl—tra~,s一4,8,12一thidacatrienal(1,3.4E,14.4 mmo1)in THF(35 mL)w鼬
added drolr,vise.It was fred over 20h.at room temperature and quenched by cautious addition of
saturated aqneous ammonium chloride. nle aqueous phase w舳 extracted witlI ether. dryi~S over
magnesium sulphate and purified by flash chromatography(petrol:ether=5:1).The title compound(2,
2.6 g,68%)was obtainad.v一 (mm):2930,2852,1655,450,1385,1210,933 and 886 om.8H:6.13—
5.66(2H,m,CH— CH),4.95(2H,m,2×一 CH),4.53—4.50(2H,m,一 CH2),3.39—3.31(3H,
m,OCHs),2.00 ~ 1.82(12H,m,6× CH2),1.55(3H,s,CHs),1.43(3H,s,CHs),
1.41(3H,s,CHs).8c:146.9(一 cH),145.9(一cH),135.1(quat.C),134.7(quat.C),
134.4(quat.C),124.4(一 CH),124.0(一 CH),109.7(一 CH2),55.7(OCH3),40.9(CH2),39.7
(CH2),39.6(CH2),37.8(CH2),26.5(CH2),26.2(CH2),22.4(CHs),15.9(CH3),15.8(CH3).
Methyl 5,9,13一tnknethylbutadeca一5,9,13一Irlenoate(3)A solution of anol ether(2,2.5 g,9.5
mmo1)in diehloromethane(20 mL)was rapidly added to a suspension of PcC(4.1窖,19.0 anno1)in
dlchloromethone(∞ mL).Afterthe mixtu弛w鼬 stirredfor 1.5 h.at loom temperature,ether(40mL)
was added to jt. nIe supematant liquid was ooured t0 a beaker and the residue solid was washed with
ether(3×20 mL).The oonlbined etheral solutions passed through a column filied with silica and
magnesium sulphate and the residue w鼬purified by flash chromatograpby (petrol:ether=5:1),the title
compound(3,1.98 g,73%)was obtained.v衄 (‰ )2934,2853,1742,1650,1436,1374,1209,1155,
887cm~.8H:5.22(2H,m,2×一 CH),4.80(1H,s,一 CH),4.77(1H,s,一 CH),3.76(3H,s,OCHs),
2.36(2H,t,J=7.6Hz,CH2),2.18—2.06(10H,m,5×CH2),1.84—1.76(2H,m,CH2),1.82(3H,s,
CH3),1.70(3H CHs),1.68(3H,s,CHs).;8c:174.4(CO),146.1(quat.C),135.2(quat.C),134.0
‘ at.c),125.5(一cH),124.4(一cH),110.0(一cH2),51.6(OCH3),39.8(cH2),39.1(CH2),
38.0(CH2),33.6(cH2),26.8(CH2),26.4(CH2),23.2(CH2),22.7(CHs),16.2(CHs),15.9(CHs).
rhe following enol ethe~ an d ester8 were synthesized similarly.
1一methoxy一5,9,13一tl'~nethyl一1,5,9,13,17—0c叫 m peta∞e(4)The title compound(4)was
0brainedfrom 4,8,12一trimethyl一4,8,12,16一heptadeeatetraenal in 75% yield. (fdm):2926,
2851,1656,1641,1450,1384,1210,911 cTn一.占H:6.14—6.09(1H,d,J=121-Iz,CH—
CHOMe),5.66—5.60(2H,m,2×一 CH),4.94~4.75(5H,m,3×一 CH +一 CH2),3.39and
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188 有 机 化 学 1999正
3.31(3H,s,OCH3),1.90—1.50(16H,m,8×CH2),1.42(9H,8,3×CH3).8c 146.8(一 CH),
145.9(一 cH),138 7(一 CH),135.4(quat.C),134.9(quat.C),134.1(quat.c),124.6(一
CH),123.7(一 CH),124.2(一 CH),I14.3(一 CH2),55.8(OCH3),39.7(2×CH2),34.0(2×
CH2),27.4(CH2),26.6(2×CH2),26.4(CH2),16.03(CH3),15.99(CHs),15.96(CH3).
1一methoxy一5,9,13,17一tetramethyl—l,5,9,13,17一ocladompetaene(5)The dtle compound
(5)waft obtained from 4,8,12,16一tetramethyl一4,8,12,16一heptadeeate~aenal in 70% yield. 一
(film):2928,2851,l655,1449,1434,1383,1210,I1I1,886em。。.占H:6.04—6.oo(1H,d,J=
12.5HzCH—CH0Me),4.92—4.85(4H,m,4×一CH),4.44(1H,s,一 CH),4.42(1H,s,一CH),
3.30 and 3.22(3H,s,OCH3),1.89—1.74(16H,m,8×CH2),1.46(3H,8,CH3),1.35(3H,s,CH3),
1.33(6H,B,2×CH3).8c:145.8(quat.C),135.1(quat.C),134.6(quat.C),133-8(一 CH),133.5(一
CH),128.6(-- CH),128.3(一 CH),124.3(quat.c),l24.0(一 cH),109.7(一 cH2),55.8(OCH3),
39.7(2×CH2),37.8(2×CH2),26.6(CH2),26.2(2×CH2),26.1(CH2),22.4(CH3),16.03(3×
CH3).
1一methoxy一17一phenyl一5, 9,13一trimethyt—l,5,9,l3,17一octadecapetaene(6) e fide
compound(6)was obtained from 16一phenyl一4,8,12一trimethyl一4,8,12,16一heptadecatetmenal in
69% yield.v (fdm):3025,2926,2851,1655,1598,1494,1448,1383,1210,I1I1,963em~.8H:6.94
— 6.74(5H,nl,5×aryl— cH),5.96—5.77(4H,m,4×一 cH),4-81—4.71(3H,m,3×一 CH),3.15
and 3.07(3H,8,0cH3),1.85—0.65(25H,m,8×CH2+3×CH3).
Methyl 5,9,13一tr'maethyl一5,9,13,17一 (7)The title compound(7)was
obtained in 75% yield.v (film):2922,2852,1742,1640,1437,1382,1245,1210,l156,944,
91lem。。.占H:5.85—5.78(1H,nl,一 CH),5.12—5.09(3H,m,3×一 CH),5.02—4.93(2H,ii1,一
CH2),3.65(3H,s,OCH3),2.28—1.97(16H,m,8×CH2),1.73—1.65(2H,m,CH2),1.60(3H,s,
CH3),1.59(3H,8,CH3),1.58(3H,s,cH3).占c:174.2(CO),138.7(一 cH),135.3(quat.C),134.8
(quat.C),133.7(quat.C),125.3(一 cH),124.3(一 cH),123.8(一 cH),114.3(一 CH2),51.4
(0CH3),39.6(2×CH2),38.9(CH2),34.0(CH2),33.4(CH2),27.4(CH2),26.6(2×CH2),23.0
(CH2),16.0(2×CH3),15.7(cH3).
Methyl 5,9,13,17一tetrametlhIyl一1,5,9,13,17一octadecapetaenoate(8)The tide compound(8)
was obtained in 60% yield.v一 ( lm):2920,1742,1649,1437,1374,1204,1155,886em一.8H:5.23—
5.18(3H,m,3×一 CH),4.80(1H,s,一 CHH),4.77(1H,8,一 CHH),3.76m(3H,8,OCHs),2.39—
2.07(16H,m,8×CH2),1-88—1.77(2H,m,CH2),1.82(3H,s,cH3),1.71(3H,s,CHs),1.69(6H,s,
2×CH3).8c:174.5(C0),145.8(quat.C),135.1(quat.C),134.7(quat.C),133.7(quat.C),125.3(一
CH),124.3(一 cH),124.0(一 cH),109.7(一 CH2),51.4(OCH3),39.6(2×CH2),38.9(CH2),37.8
(cH2),33.4(cH2),26.6(2×CH2),26.2(CH2),23.0(CH2),22.4(CH3),15.9(2×cH3),15.7
(CH3).
Methyl17一phenyl一5,9,13一trimethyl一1,5,9,13,17一octadecapetacnoate(9) etitle compound
(9)was obtained in 68% yield.v一 (fdm):3024,2955,2925,1741,1598,1494,1436,1381,l155,
963em-1.8H:7.41—7.21(5H,m,5×aryl— CH),6.49—6.27(2H,m,CH— CH),5.26—5.18(3H,
m,3×一 CH),3.72(3H,s,OCHs),2.35一1.74(18H,m,9×CH2),1.69(3H,s,CH3),1.65(3H
CH3),1.61(3H,8,CH3).占c:173.6(CO),137.9(quat.C),135.6(quat.C),134.8(quat.C),133.7
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第 2期 陈立功等 :从 4一戊烯醛经增碳反应合成 5一己烯酸甲醑类化合物 189
(quat.C),130.6(一 cH),129.9(一 cH),128.4(2×aryl— cH),126.7(aryl— cH),125.9(2×aryl
— CH),125.3(一 CH),124.3(一 CH),123.6(一 CH),51.3(OCH3),39.7(CH2),39.6(CH2),38.9
(CH2),37.8(CH2),33.4(CH2),33.3(CH2),27.8(CH2),27.77(CH2),27.6(CH2),26.6(CH2),
16.05(CH3),15.96(CH,),15.7(CH3).
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Synthesis of Methyl 5--hexenates by Homologation
of 4--pentenals
CHEN Li—Gong , LI Yang,
MENG Yi, LI Yuan, LU Meng, LUO Hui—Bing, WANG Yong
(Applied Chemistry andFine ChemicalsD m of
Chemla~Engineering School ofn口n枷 University,300072 )
Abstract Methyl 5.9,13一trimethylbutadeca一5.9,13一trienoate(3)and methyl 5一hexenate~
(7—9)were synthesized by homologation of 4,8,12一trimethyl一4,8,12一trideeatrlenal(1)and 4一
pentenals.Thus,ll~ ent of 4一pent~nals with methoxy methylenetriphenylphosphin afforded a mixture
of c/s— an d troats— enol ethers,which were oxidized by PCC to give methyl 5一hexenates.
Key words Witfig reaction,PCC oxidation,all trans-polyene esteTB,one—carbon homologation
(Ed.Shan H)
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