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Crystalline dipentadienylzinc. Preparation, conformational analysis and chemical reactivity
Porgwu
TetxabedronLetters Ho. 1, P) 11 - 14, 19%
Promo. Printed in WmtBrit8in.
CRYSTALLINEDIPKWTADIKWYL2IKC.PKKPAKATIOW, COWFOREIATICWALAWAIYSIS AWD CHKKICALREACTIVITY
Hajima Yasuda and Hisaya Tan1 Departmentof Polymer Science,Faculty of Science, Osaka University,Toyocaka,Osaka 560, Japm (Keoemd
in Japm 3 October1974;reoeimd in UK for pblioatioa 26 Ilovo~ber 1974)
Preparationsof acyclicdienylmetalcompoundshave received little attentionexcept for l-4 dienylalkalillletal compouuds , while the preparatim, conformationalaualysisand reactionof a number of allylmetalconpoundshave been studied extensively5. We wish to describeherein a generalprocedure for the preparation,conforwationalanalysisand so= chemicalreactionsof dipentadienylzinc compounds,since several crystallinedienylalkalimetal compoundshave became readily available3. Dipentadienylzinc-tetrahydrofuranate 1 (mp. -10') was isolated aa needles by reacting crystallinepentadienylpotassiumwitha half equimole of anhydrouszinc dichloridein tetrahydrofuranat -2O', evaporatingthe excess amomt of tetrahydrofurim, extractingfrom the residuewith n-peutcmeand then cooling the n-pentcmesolution to -78' to induce crystallization.
All procedureswere carried out in an argon atmospherebelow O', aa _&was thermally
unstable. Thermal decoapositicnof ibegan at 10' and the half life time at 30' was 10 min. which was preparedby adding five moles equivalenceof triethylamlneto 1 in n-pentme solutioo and cooling the solution to -50°, also decomposedat room temperatureto trras,trans-1,3,7,9-decatetreened,
1
+lO"
/-llvbw +
11
+ Zn
Ho. 1
12
triene and metallic zinc. Thehalf life tips at30* of2wss
15 ndn. Therskllystable di-
pentadienylslncccspounds were isolatedwvlng awmodentate llgmdhaving avery etrmgbasicity or a bidentate ligand. The 1:l complex of dip~tadienylein~trimethylamLneofide 2 (xp. (TMgDA)115°) was stsble at 80' in toluene ss well as N,N,N',N'-tetramthylethylenedlamine pentadienylsinc~ (mp. 58') and N,N,N',N'-tetrasethylpropylenediaurfne (TWPDA)-pentadlenylsinc 2 (mp. 50.50). The molecularweights of 1, &2,1
and2 determinedcryoscopicallyin benzene
correspmd to those of mcnowaric1:l complexes. EaQ of the cmr spectrum of 1.2
mdzin
d6-benseneat 6' shcwed three peahe (Table l), whim suggest that these coapomds msuaw II-or W-shaped cmforaetim ammg the three pmeible plmar cmfornetlme; U(de-&I)-, W(trmetrms)- md ei&le(cie-trms)-shaped cmfonnatims'.
Table 1. Carbm-13 nmr Chewical Shift of PentadienylzlncConpomds
a.
c4
c5
118.2
147.1
105.0
118.3
148.0
104.2
c1
c2
c3
Zn(C5S7)2*THP 1
65.3
139.2
115.3
2n(C5g,)2*Wgt3 2
66.9
140.0
121.3
2n(C5D,)2'm3
66.0
144.9
117.4
2n(C5X7)2'TnsDAQ
20.5
141.0
Zn(C,H,),*TMPDA5
19.7
140.4
2
In ppm downfieldfrom internal
a.b
TWSin d6-benzene(calibratedusing the d6-benzenepeak,
assumed to be 128.0 ppw). Data were collectedat 25.2 l4isat 6' m
a Varlm KlOO-15
spectrometerequippedwith a Mgilab Wo&lPTS-NMB-3 Fourier trmsform accessory. b. Peak assignmentswere wade in part from m
off-resmmm
decoupledspectrum.
Pmr mendcal shift of 1, 2 md 2 observedin d6-benzeneat 6' md the protm-protm ing cmstmt,
coupl-
8 J23, of ca. 12 Hz correspmd to trms conforwatim . The coupling constmt, J12,
of ca. 11.4 Bz correspondswell to an intermdiate value between outer bond-&v, 7.5-9.0Hz and outer band-traus,16 HE*. Thus, the planar canformationsof 1.2
snd3were
W-shaped. Ir absorptims at 950(trms 6CW) and l.620m-l(vC-C) of i,L also consistentwith the W-shaped cmfonnatlm. were sharply differentfrom those of 2 md1.
determinedto be
wdzin
benzene are
Paw spectra of 5 and 2 in d6-benzeneat 6" The west strikLng feature of the spectra is that
a doubletprotm peah,whicb is r~leig~able to a methyleneprotm of pentadienyl
group
bmded
with zinc metal by u-bmd, WBB observedin higher field (ca. 1.43 ppm damfield from external TE in d6-benseneat 6'). Cxu spectra at 6' in d6-benzenegave ftve peshs for? md 2.
The
lie.
13
1
structure
of 4 or 2 was, therefore,
delocalized (v*c)
carbmim
support
this
form.
Ir
cmcludad
sbsorptions
cmclusim.
whi&
bonded structurs ble
is
cmsistent
BJI elevating
only when the bidentate
spectra
of 1 md 2 also
with the structure matlms
of 1, 1 md2
rewrslwly
of 2 md 2 at 6’)
of 1 md 2 helm
to be terndnaliy
Qmged
coordinate
a-boa&d
at 6’,
pentadiene in 50-70,
all
suggests
cad W-shaped delocalized loosely
to zinc metal.
them to -60’ as well
This result
by hydrolysis
b
\
8’
A?& ,’
’
_
4
suggest
md 1,4-
benseue at 6’.
;N-N'
\.,,/
The formation of’ cis-1,3-pentadlene
from that
cis-1,3-pentadiena
‘;zpyy=
WBB explained by (II equilibrium
pw
structure(consistant
of 4 md 2 is different
1
1
is possi-
Co the other hmd,
a-bmded
l+y 2
4’
as k md 2 at room temperature fomd
Although the structure
respectively,
structure
In dg-TIXP. Tbux, the cmfor-
these cowpomds gave a mixture of trans-,
W’_
*
that terminally
to that of terminally
6-13 end 20-40X yield,
LJ
Model erawinatim
the temperature at -60’ structure.
1, 2 md
to that of W-shaped
by cooling
9
the ~ornde
of 4 md 2 chmged reversibly
suet favorable
ligmd
form, not a centrally 6Ui) cod 1620 cm”
the temperature up to 80’.
with a formula 3’.
5 Is sterically
o-bmded
of both 4 md 2 at 970(tr(as
2 were decomposed completely but pwr spectra structure,
to be a terminally
‘.*
,,’
_
6’ eldsting
between A md B in the reactim
that the barrier
to rotation
system.
about the inner bmd
of B would be small. zn
Zn
A The reactims
propylketme alcohols.
B
of pentadienylsinc
g md di-isopropylkatme The yield
the increase
2 resulted
of the product reacted
in bulkiness
of m alkyl
pound having less bulky groups favored structure
cos~omds with acetaldehy&
A to give mly
dienyl
at Cl of pantadlenyl to carbmyl
equflibrium
alcohol
a&tone 2, methyl-iso-
in the formation of additim
group atteQed
was reacted,
2,
reacted
edstlng
products,
group increased group.
dienyl
with
when the carbmyl
In the reactim
at C3 of pentadienyl
system
group.
These
cop
u
lo.
dienylalcchob
1
couldnot be obtadneddirectlylimingpentadienylalkaUmtel co~0uldB,aa al&l
condensationoccurredpreferentially. above. will be useful aa a general method for the
In conclusion,the reactianamutimed
preparatim of anrrmberof dienylmtal canpoundsand of orgmic dienyl derivativee. Table 2. PercentageYield of the Producte Reacted at Cl ard C3 Atome of Pentadienykincwith CarbonylConpourdtra. Carbcnyl canpd. Reactim site
a.
a
I c3
c1
s
c1
c3
c1
9 c3
Cl
1
0.0
100.0
0.0
100.0
50.2
49.8
92.0
c3 8.0
2
0.0
100.0
0.0
100.0
96.0
4.0
98.0
2.0
G
0.0
100.0
0.0
100.0
97.5
2.5
98.5
1.5
5
0.0
100.0
0.0
100.0
97.6
2.4
99.0
1.0
Characterizedby pm, ma8 Imd ir after reactingboth coPponentein benzene at 6' for lhr, hydrolyzingat 6' md isolatingea& fractionby preparativeglpc. RRFERRNGES
1. B.B.Batea,D.W.Goseelink,md J.A.Kaczynski,TetrahedrcmIett., 2,199(1967);R.B.Bates, S.Brenner,ilndC.M.Cole,J. Amer. &em. Sot., 9&2130(1972); R.B.Batee,W.B.Deinee, D.A.McConbs,axd D.E.Potter,ibid.,9l,4608(1969);R.B.Bates,S.Brenner,C&Cole, E.W.PavlCcn. G.D.Fonsythe,D.A.McConbe,md A.S.Roth,ibid., 95,926(1973) 2. G.J.Reisewolf,J.A.A. vgl D-en,
md H.Klooeterxlel,Reel. Trav. (him. Pays-Baa,88.1377
(7969);H.Kloceterzielmd J.A.A. vax Drmen, ibid., 89,270(1970);H.Klooeterzieland J.A.A. vm Dru~en, ibid., 89,368(1970) 3. H.Yeruda,T.Narita, md H.Tani, TetrahedrcmLett., 27,2443(1973) 4. W.T.Ford md M.Newconb,J. hr.
them. Sot., 96,309(1974)
a-ally1 type structure. H.Gaude=r, Bull. 5. For example, allylzincis cansiderndto aesllpe Sot. Chim. Fr., 974(1962);K.H.Thielemd P.Zdmneck, J. Organ-tal. &em., &10(1965) 6. By llsing Ni(II) chlorideor Co(U) chloride,in place of dichlorozinc,mly 1,3,7,9decatetrawe wae obtained. 7. A.Bridcstockand J.A.Pople,Trans. Faradq Sot., 50,9Ol(l954);R.Hoffmn
end R.A.Olofsm,
J. Amer. (hem. Sot., SS,943(1966) 6.5 Ez md J23(trrms)-12HE. R.B.Batee,D.W.Gmselink, md 8. Normally Jg3(cia)-ccl. J.A.Kauynski, Tetrhedrcn Lett., &205(1967) 9. It is noteworthythat the coordinationof a bidantate ligmd, diethyleneglycoldirethylether, resultedin the W-shaped oar&rally&localized canformation,while bidentate tertiarydiandne coxplex asallpeternduallybonded structure at 6'.
TetxabedronLetters Ho. 1, P) 11 - 14, 19%
Promo. Printed in WmtBrit8in.
CRYSTALLINEDIPKWTADIKWYL2IKC.PKKPAKATIOW, COWFOREIATICWALAWAIYSIS AWD CHKKICALREACTIVITY
Hajima Yasuda and Hisaya Tan1 Departmentof Polymer Science,Faculty of Science, Osaka University,Toyocaka,Osaka 560, Japm (Keoemd
in Japm 3 October1974;reoeimd in UK for pblioatioa 26 Ilovo~ber 1974)
Preparationsof acyclicdienylmetalcompoundshave received little attentionexcept for l-4 dienylalkalillletal compouuds , while the preparatim, conformationalaualysisand reactionof a number of allylmetalconpoundshave been studied extensively5. We wish to describeherein a generalprocedure for the preparation,conforwationalanalysisand so= chemicalreactionsof dipentadienylzinc compounds,since several crystallinedienylalkalimetal compoundshave became readily available3. Dipentadienylzinc-tetrahydrofuranate 1 (mp. -10') was isolated aa needles by reacting crystallinepentadienylpotassiumwitha half equimole of anhydrouszinc dichloridein tetrahydrofuranat -2O', evaporatingthe excess amomt of tetrahydrofurim, extractingfrom the residuewith n-peutcmeand then cooling the n-pentcmesolution to -78' to induce crystallization.
All procedureswere carried out in an argon atmospherebelow O', aa _&was thermally
unstable. Thermal decoapositicnof ibegan at 10' and the half life time at 30' was 10 min. which was preparedby adding five moles equivalenceof triethylamlneto 1 in n-pentme solutioo and cooling the solution to -50°, also decomposedat room temperatureto trras,trans-1,3,7,9-decatetreened,
1
+lO"
/-llvbw +
11
+ Zn
Ho. 1
12
triene and metallic zinc. Thehalf life tips at30* of2wss
15 ndn. Therskllystable di-
pentadienylslncccspounds were isolatedwvlng awmodentate llgmdhaving avery etrmgbasicity or a bidentate ligand. The 1:l complex of dip~tadienylein~trimethylamLneofide 2 (xp. (TMgDA)115°) was stsble at 80' in toluene ss well as N,N,N',N'-tetramthylethylenedlamine pentadienylsinc~ (mp. 58') and N,N,N',N'-tetrasethylpropylenediaurfne (TWPDA)-pentadlenylsinc 2 (mp. 50.50). The molecularweights of 1, &2,1
and2 determinedcryoscopicallyin benzene
correspmd to those of mcnowaric1:l complexes. EaQ of the cmr spectrum of 1.2
mdzin
d6-benseneat 6' shcwed three peahe (Table l), whim suggest that these coapomds msuaw II-or W-shaped cmforaetim ammg the three pmeible plmar cmfornetlme; U(de-&I)-, W(trmetrms)- md ei&le(cie-trms)-shaped cmfonnatims'.
Table 1. Carbm-13 nmr Chewical Shift of PentadienylzlncConpomds
a.
c4
c5
118.2
147.1
105.0
118.3
148.0
104.2
c1
c2
c3
Zn(C5S7)2*THP 1
65.3
139.2
115.3
2n(C5g,)2*Wgt3 2
66.9
140.0
121.3
2n(C5D,)2'm3
66.0
144.9
117.4
2n(C5X7)2'TnsDAQ
20.5
141.0
Zn(C,H,),*TMPDA5
19.7
140.4
2
In ppm downfieldfrom internal
a.b
TWSin d6-benzene(calibratedusing the d6-benzenepeak,
assumed to be 128.0 ppw). Data were collectedat 25.2 l4isat 6' m
a Varlm KlOO-15
spectrometerequippedwith a Mgilab Wo&lPTS-NMB-3 Fourier trmsform accessory. b. Peak assignmentswere wade in part from m
off-resmmm
decoupledspectrum.
Pmr mendcal shift of 1, 2 md 2 observedin d6-benzeneat 6' md the protm-protm ing cmstmt,
coupl-
8 J23, of ca. 12 Hz correspmd to trms conforwatim . The coupling constmt, J12,
of ca. 11.4 Bz correspondswell to an intermdiate value between outer bond-&v, 7.5-9.0Hz and outer band-traus,16 HE*. Thus, the planar canformationsof 1.2
snd3were
W-shaped. Ir absorptims at 950(trms 6CW) and l.620m-l(vC-C) of i,L also consistentwith the W-shaped cmfonnatlm. were sharply differentfrom those of 2 md1.
determinedto be
wdzin
benzene are
Paw spectra of 5 and 2 in d6-benzeneat 6" The west strikLng feature of the spectra is that
a doubletprotm peah,whicb is r~leig~able to a methyleneprotm of pentadienyl
group
bmded
with zinc metal by u-bmd, WBB observedin higher field (ca. 1.43 ppm damfield from external TE in d6-benseneat 6'). Cxu spectra at 6' in d6-benzenegave ftve peshs for? md 2.
The
lie.
13
1
structure
of 4 or 2 was, therefore,
delocalized (v*c)
carbmim
support
this
form.
Ir
cmcludad
sbsorptions
cmclusim.
whi&
bonded structurs ble
is
cmsistent
BJI elevating
only when the bidentate
spectra
of 1 md 2 also
with the structure matlms
of 1, 1 md2
rewrslwly
of 2 md 2 at 6’)
of 1 md 2 helm
to be terndnaliy
Qmged
coordinate
a-boa&d
at 6’,
pentadiene in 50-70,
all
suggests
cad W-shaped delocalized loosely
to zinc metal.
them to -60’ as well
This result
by hydrolysis
b
\
8’
A?& ,’
’
_
4
suggest
md 1,4-
benseue at 6’.
;N-N'
\.,,/
The formation of’ cis-1,3-pentadlene
from that
cis-1,3-pentadiena
‘;zpyy=
WBB explained by (II equilibrium
pw
structure(consistant
of 4 md 2 is different
1
1
is possi-
Co the other hmd,
a-bmded
l+y 2
4’
as k md 2 at room temperature fomd
Although the structure
respectively,
structure
In dg-TIXP. Tbux, the cmfor-
these cowpomds gave a mixture of trans-,
W’_
*
that terminally
to that of terminally
6-13 end 20-40X yield,
LJ
Model erawinatim
the temperature at -60’ structure.
1, 2 md
to that of W-shaped
by cooling
9
the ~ornde
of 4 md 2 chmged reversibly
suet favorable
ligmd
form, not a centrally 6Ui) cod 1620 cm”
the temperature up to 80’.
with a formula 3’.
5 Is sterically
o-bmded
of both 4 md 2 at 970(tr(as
2 were decomposed completely but pwr spectra structure,
to be a terminally
‘.*
,,’
_
6’ eldsting
between A md B in the reactim
that the barrier
to rotation
system.
about the inner bmd
of B would be small. zn
Zn
A The reactims
propylketme alcohols.
B
of pentadienylsinc
g md di-isopropylkatme The yield
the increase
2 resulted
of the product reacted
in bulkiness
of m alkyl
pound having less bulky groups favored structure
cos~omds with acetaldehy&
A to give mly
dienyl
at Cl of pantadlenyl to carbmyl
equflibrium
alcohol
a&tone 2, methyl-iso-
in the formation of additim
group atteQed
was reacted,
2,
reacted
edstlng
products,
group increased group.
dienyl
with
when the carbmyl
In the reactim
at C3 of pentadienyl
system
group.
These
cop
u
lo.
dienylalcchob
1
couldnot be obtadneddirectlylimingpentadienylalkaUmtel co~0uldB,aa al&l
condensationoccurredpreferentially. above. will be useful aa a general method for the
In conclusion,the reactianamutimed
preparatim of anrrmberof dienylmtal canpoundsand of orgmic dienyl derivativee. Table 2. PercentageYield of the Producte Reacted at Cl ard C3 Atome of Pentadienykincwith CarbonylConpourdtra. Carbcnyl canpd. Reactim site
a.
a
I c3
c1
s
c1
c3
c1
9 c3
Cl
1
0.0
100.0
0.0
100.0
50.2
49.8
92.0
c3 8.0
2
0.0
100.0
0.0
100.0
96.0
4.0
98.0
2.0
G
0.0
100.0
0.0
100.0
97.5
2.5
98.5
1.5
5
0.0
100.0
0.0
100.0
97.6
2.4
99.0
1.0
Characterizedby pm, ma8 Imd ir after reactingboth coPponentein benzene at 6' for lhr, hydrolyzingat 6' md isolatingea& fractionby preparativeglpc. RRFERRNGES
1. B.B.Batea,D.W.Goseelink,md J.A.Kaczynski,TetrahedrcmIett., 2,199(1967);R.B.Bates, S.Brenner,ilndC.M.Cole,J. Amer. &em. Sot., 9&2130(1972); R.B.Batee,W.B.Deinee, D.A.McConbs,axd D.E.Potter,ibid.,9l,4608(1969);R.B.Bates,S.Brenner,C&Cole, E.W.PavlCcn. G.D.Fonsythe,D.A.McConbe,md A.S.Roth,ibid., 95,926(1973) 2. G.J.Reisewolf,J.A.A. vgl D-en,
md H.Klooeterxlel,Reel. Trav. (him. Pays-Baa,88.1377
(7969);H.Kloceterzielmd J.A.A. vax Drmen, ibid., 89,270(1970);H.Klooeterzieland J.A.A. vm Dru~en, ibid., 89,368(1970) 3. H.Yeruda,T.Narita, md H.Tani, TetrahedrcmLett., 27,2443(1973) 4. W.T.Ford md M.Newconb,J. hr.
them. Sot., 96,309(1974)
a-ally1 type structure. H.Gaude=r, Bull. 5. For example, allylzincis cansiderndto aesllpe Sot. Chim. Fr., 974(1962);K.H.Thielemd P.Zdmneck, J. Organ-tal. &em., &10(1965) 6. By llsing Ni(II) chlorideor Co(U) chloride,in place of dichlorozinc,mly 1,3,7,9decatetrawe wae obtained. 7. A.Bridcstockand J.A.Pople,Trans. Faradq Sot., 50,9Ol(l954);R.Hoffmn
end R.A.Olofsm,
J. Amer. (hem. Sot., SS,943(1966) 6.5 Ez md J23(trrms)-12HE. R.B.Batee,D.W.Gmselink, md 8. Normally Jg3(cia)-ccl. J.A.Kauynski, Tetrhedrcn Lett., &205(1967) 9. It is noteworthythat the coordinationof a bidantate ligmd, diethyleneglycoldirethylether, resultedin the W-shaped oar&rally&localized canformation,while bidentate tertiarydiandne coxplex asallpeternduallybonded structure at 6'.