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Carbon-to-carbon coupling constants - a new guide in the stereochemistry of heteroatomic compounds
Journal of Molecular Structure, 143 (1986) 569-572 Elsevier Science Publishers B.V., Amsterdam
-Printed
569 in The Netherlands
CARBOY-TO-GARBOI COUPLIMO COliSTAHTS- A HBW GUIDE IN THE STEREOCHWISTRY 03'IiF,TlBOATOHIC COHPOUHDS G.A.KALABd
, L.B.KRIVDIE+, V.V.SRCRRRBbw)V' and B.A.TROFIHOV* 'Chemietry Dept., Univereity of Irkut8k, 664003 Irkutsk (USSR) *Inet.Org.Chem. Ao. Soi. USSR, 664033 Irkutek (USSR)
ABSTRACT A 8ub8tantial poeitive oontrlbution to the direot 13c-13c‘8piZIrpln ooupling oonatanta ha8 been demonetrated to be induoed by the proximity of the nitrogen and oxygen lone pair8 In eie-orlentstion to the neighbowing ooupllng oarbon nuolei. IHTRODUCTIOI In the reoent deoade the utmst intere8t has been focused on oarbon-to-carbon 8pin-8pin ooupllng oon8tante ('Jo,) in reepeot to eluoidation of bioaynthetio pathway8 a8 Well a8 a variety of 8tIWOttWal problem8 dealing with OOnfoI'm8tional8tudie8, 8ubetitution effeoto, oharaoterl8ation of oarbon-oarbon bond8 by eetimation of a-oharaatere, r-Order8, fOme atretohlag oonetants and traoing oarbon eoeleton of large organio moleoulea via determlnation of oonneotivity pattern8 (ref.l.2). Very scaroe lnforrrtion i8 known about the heteroatom lone pair effeot on 'Jo0 while a good deal of data 18 available on nitrogen and oxygen lone pair effeota on oarbon-to-hydrogen ooupling conatante of the neighbouring dlreotly bonded nuolei (ref.3,4). The aim of the present paper i8 to demonstrate the etereoapeoifity of 'Jo, to the orientationof the heteroatorlone paire. BITROGIW LONE
PAIFiEFFECT
Oximee and related com~ounda Beeently we have dlsoorered (ref.51 a dramatio poritlre oontributlon of oa. 7-l 1 Ii8to 'Jo. in oxlmea induoed by the proximity of the nitrogen lone pair In eie-orientation to the adjaoent ooupled oarbon nUOlei. It ie noteworthy th8t ‘Jeo ill ilinr8 pOS808~ the 88me feature (see Table 1) and therefore rsy serve aa a Clue t0 unnslb~iOU8 OOIlfi&ll'atiO~ a88i@mlt Of iairU nitrogen. 0 1986Elsevier 0022-2860/86/$03.50
Science Publishers B.V.
570
TABLE 1
Carbon-aarbon#pin-epinoouplingconstant6(He) in the functional imines 'J,,(z)
XAc-Y II
ZHN
colnpouIldx
Y
1
Et
s 4 5 !
a
:; 16 z :z
R Me :
:ii
Me He Ph
zH(Me)OPr
:: ~~~::
Ph :
~H(Jk)OPr iH(Me )OPr
2-thienyl 2-thienyl COMe COOHe COOUe COOMe COOYe COOEt
Me Me COMe COOMe 00OMe
0CIi=CH2 OH t-Bu
COOMe
&
COOEt
COOxe COOEt cOOl%t COOEt
COOMe
COOMe
0CH2Ph OTa OCOYe OCOPh Cl
CooEt
s: 23
;MeCOOC6H4
i Me Me ::
9
::
z
giBrc6'4 OH OCH(Me)OPr
'J&Z)
'J&E)
30.4 38.0 30.1 41.4 ;t*t
t;.*;
g:;
48:0 49.3 62.8 5:*; 61:5
;::; ;;:i
SO:5 5X
60:4 59.8
$?Z 70:o 58.5 85.7 87.9 87.8
47:*: 75:3 75.1
::*; 83:a 83.4 80.9
~XYOEE LOBE PAIR EFFECT Vizwl etherm The vinyl ethere is known to exiet in the equilibriumof e-oie and e-tram oonformere eaoh with a poeeibleout-of-planedeviation of the R moiety. H
H
H)_(
o0B r-tram
The predominantoonformerof methyl-vinylether g& hae been proved to be s-oin while in the oaee of tert-butylviayl ether $Q the equilibriumis shiftedtowards mew e-trana form.
571
The value of the direct spin-spinooupllngoonstantebetween olefiniocarbon8 in the former compoundis oa. 4 Ii5 more positive than that of the ether a. This differenoeshould be aeoribedto the ap2-hybrid&tedoxygen lone pair effect on 'Jo0 in the e-oie oonformerof vinyl ethera. Data preeentedin Table 2 demonetrate the predominant oonformation of aromaticand heteroaromatio vinyl ethers (ompde 3,7-53) to be e-tram. Thie findingie in a good agreementwith previoue atudiee (ref.6).A rather pusslingreeult llee in the fact that 'Jok in arylvlnylethers ehose no dependenoeon C-electroneffeote of the eubetituentin the aromatiomoiety (ompde.3,7-$,Ej). TABLE 2 Carbon-oarbon
spin-opin
ooupling oonatante (Hs) in vi41
ethers
compound B
n-Pr n-Bu i-Pr a-Bu t-Bu CH2Ph ;:$2g2
'JO0 78.6 78.5
78.6 78.7 79.6 80.1 82.2 79.2 79.3 78.4
compound B 43
'Jo0
P_MO2C6H4 'p-,ki0c6H4 p-HeOCgH4 p-CH2=CHOC6H4 p-C1C6H4
48
81.7 81.4 81.4 82.1 81.7
49
80.9
50
81.4
51
82.0
44 45 46 47
34
(CH;I;-h
78.3
3s
m2)2-N~0
78.9 81.2 81.8 81.0 81.6 81.4 81.5
54
41
clim2 Ph o-bC6H4 m-MeC6H4 p-ueC6ii4 lll-~tCOOC6H4
55
’ 6, co
42
m-H02C6H4
81.8
56
SlMe3
;i 39 40
81.4
;s
COMe
COPh co f
-0
82.5 83.0 82.5 81.0 80.2
572
Confornretionalequiliblum of 4,4,5-trimethyl-l,3_dioxanez is ehifted touarde the oonformer A (ref.7). Two methyl groups at C-4 are not equivalent 8nd therefore lJ4 7 8nd 'j4 8 can be eaeily meaeured 8nd unaabigiouely aeeigned (42.5 and 34.0 HE reepeotively). The value of 1J4,7 ie 3.5 Hz more positive than lJ4 8 ,
due to the poeitive oontributioa of 8n axial ap3-hybridlsed oxygen lone pair to 8 former constant:
We have found further proof8 of the oxygen lone pair effeut on ‘Jo, whioh 8re not dlsouswd here.
We hope presented nrsterlalwill find its application In eolving etereoohemioal probleme dealing with the apatial orientation of the heteroatomio lone pair in 8 wide variety of heteroatomio oompounds. ACKWOWLEDGEHBNT The author8 are grateful to Dr. A.V.Proeyanik for providing them with cmpde. 1-2, 12-a.
REFERENCES
1 2 3 4 5 6 7
V.Wray, Progr. WMR Spectroeo., 13 (19791, 177-256. P.E.Haneen, Ann. Repte. NWR Speotroeo., 1lA (19811, 65-98. K.Book, LWiebe, Aota Chem. Soand., 27 (1973) 2676-2678. R.R.Fraeer, Y.Bresee, Can. J. Chem., 61 (1983j, 576-578. L.B.Krlvdin, G.A.Kalabln, R.N.Beeterenko, B.A.Trofimov, Tetr8hedron Lett., 25 (19841, 4817-4820. G.A.ICalabin,D.F.Kushnarev, R.B.Valeyev, B.A.Trofimov, M.A.Fedotov, Org.Yagn.Heeon., 18 (19821, l-9. G.Y.Kellie, F.G.Riddell, J.Chem.Soc. B, 5 (i971), 1030-1034.
-Printed
569 in The Netherlands
CARBOY-TO-GARBOI COUPLIMO COliSTAHTS- A HBW GUIDE IN THE STEREOCHWISTRY 03'IiF,TlBOATOHIC COHPOUHDS G.A.KALABd
, L.B.KRIVDIE+, V.V.SRCRRRBbw)V' and B.A.TROFIHOV* 'Chemietry Dept., Univereity of Irkut8k, 664003 Irkutsk (USSR) *Inet.Org.Chem. Ao. Soi. USSR, 664033 Irkutek (USSR)
ABSTRACT A 8ub8tantial poeitive oontrlbution to the direot 13c-13c‘8piZIrpln ooupling oonatanta ha8 been demonetrated to be induoed by the proximity of the nitrogen and oxygen lone pair8 In eie-orlentstion to the neighbowing ooupllng oarbon nuolei. IHTRODUCTIOI In the reoent deoade the utmst intere8t has been focused on oarbon-to-carbon 8pin-8pin ooupllng oon8tante ('Jo,) in reepeot to eluoidation of bioaynthetio pathway8 a8 Well a8 a variety of 8tIWOttWal problem8 dealing with OOnfoI'm8tional8tudie8, 8ubetitution effeoto, oharaoterl8ation of oarbon-oarbon bond8 by eetimation of a-oharaatere, r-Order8, fOme atretohlag oonetants and traoing oarbon eoeleton of large organio moleoulea via determlnation of oonneotivity pattern8 (ref.l.2). Very scaroe lnforrrtion i8 known about the heteroatom lone pair effeot on 'Jo0 while a good deal of data 18 available on nitrogen and oxygen lone pair effeota on oarbon-to-hydrogen ooupling conatante of the neighbouring dlreotly bonded nuolei (ref.3,4). The aim of the present paper i8 to demonstrate the etereoapeoifity of 'Jo, to the orientationof the heteroatorlone paire. BITROGIW LONE
PAIFiEFFECT
Oximee and related com~ounda Beeently we have dlsoorered (ref.51 a dramatio poritlre oontributlon of oa. 7-l 1 Ii8to 'Jo. in oxlmea induoed by the proximity of the nitrogen lone pair In eie-orientation to the adjaoent ooupled oarbon nUOlei. It ie noteworthy th8t ‘Jeo ill ilinr8 pOS808~ the 88me feature (see Table 1) and therefore rsy serve aa a Clue t0 unnslb~iOU8 OOIlfi&ll'atiO~ a88i@mlt Of iairU nitrogen. 0 1986Elsevier 0022-2860/86/$03.50
Science Publishers B.V.
570
TABLE 1
Carbon-aarbon#pin-epinoouplingconstant6(He) in the functional imines 'J,,(z)
XAc-Y II
ZHN
colnpouIldx
Y
1
Et
s 4 5 !
a
:; 16 z :z
R Me :
:ii
Me He Ph
zH(Me)OPr
:: ~~~::
Ph :
~H(Jk)OPr iH(Me )OPr
2-thienyl 2-thienyl COMe COOHe COOUe COOMe COOYe COOEt
Me Me COMe COOMe 00OMe
0CIi=CH2 OH t-Bu
COOMe
&
COOEt
COOxe COOEt cOOl%t COOEt
COOMe
COOMe
0CH2Ph OTa OCOYe OCOPh Cl
CooEt
s: 23
;MeCOOC6H4
i Me Me ::
9
::
z
giBrc6'4 OH OCH(Me)OPr
'J&Z)
'J&E)
30.4 38.0 30.1 41.4 ;t*t
t;.*;
g:;
48:0 49.3 62.8 5:*; 61:5
;::; ;;:i
SO:5 5X
60:4 59.8
$?Z 70:o 58.5 85.7 87.9 87.8
47:*: 75:3 75.1
::*; 83:a 83.4 80.9
~XYOEE LOBE PAIR EFFECT Vizwl etherm The vinyl ethere is known to exiet in the equilibriumof e-oie and e-tram oonformere eaoh with a poeeibleout-of-planedeviation of the R moiety. H
H
H)_(
o0B r-tram
The predominantoonformerof methyl-vinylether g& hae been proved to be s-oin while in the oaee of tert-butylviayl ether $Q the equilibriumis shiftedtowards mew e-trana form.
571
The value of the direct spin-spinooupllngoonstantebetween olefiniocarbon8 in the former compoundis oa. 4 Ii5 more positive than that of the ether a. This differenoeshould be aeoribedto the ap2-hybrid&tedoxygen lone pair effect on 'Jo0 in the e-oie oonformerof vinyl ethera. Data preeentedin Table 2 demonetrate the predominant oonformation of aromaticand heteroaromatio vinyl ethers (ompde 3,7-53) to be e-tram. Thie findingie in a good agreementwith previoue atudiee (ref.6).A rather pusslingreeult llee in the fact that 'Jok in arylvlnylethers ehose no dependenoeon C-electroneffeote of the eubetituentin the aromatiomoiety (ompde.3,7-$,Ej). TABLE 2 Carbon-oarbon
spin-opin
ooupling oonatante (Hs) in vi41
ethers
compound B
n-Pr n-Bu i-Pr a-Bu t-Bu CH2Ph ;:$2g2
'JO0 78.6 78.5
78.6 78.7 79.6 80.1 82.2 79.2 79.3 78.4
compound B 43
'Jo0
P_MO2C6H4 'p-,ki0c6H4 p-HeOCgH4 p-CH2=CHOC6H4 p-C1C6H4
48
81.7 81.4 81.4 82.1 81.7
49
80.9
50
81.4
51
82.0
44 45 46 47
34
(CH;I;-h
78.3
3s
m2)2-N~0
78.9 81.2 81.8 81.0 81.6 81.4 81.5
54
41
clim2 Ph o-bC6H4 m-MeC6H4 p-ueC6ii4 lll-~tCOOC6H4
55
’ 6, co
42
m-H02C6H4
81.8
56
SlMe3
;i 39 40
81.4
;s
COMe
COPh co f
-0
82.5 83.0 82.5 81.0 80.2
572
Confornretionalequiliblum of 4,4,5-trimethyl-l,3_dioxanez is ehifted touarde the oonformer A (ref.7). Two methyl groups at C-4 are not equivalent 8nd therefore lJ4 7 8nd 'j4 8 can be eaeily meaeured 8nd unaabigiouely aeeigned (42.5 and 34.0 HE reepeotively). The value of 1J4,7 ie 3.5 Hz more positive than lJ4 8 ,
due to the poeitive oontributioa of 8n axial ap3-hybridlsed oxygen lone pair to 8 former constant:
We have found further proof8 of the oxygen lone pair effeut on ‘Jo, whioh 8re not dlsouswd here.
We hope presented nrsterlalwill find its application In eolving etereoohemioal probleme dealing with the apatial orientation of the heteroatomio lone pair in 8 wide variety of heteroatomio oompounds. ACKWOWLEDGEHBNT The author8 are grateful to Dr. A.V.Proeyanik for providing them with cmpde. 1-2, 12-a.
REFERENCES
1 2 3 4 5 6 7
V.Wray, Progr. WMR Spectroeo., 13 (19791, 177-256. P.E.Haneen, Ann. Repte. NWR Speotroeo., 1lA (19811, 65-98. K.Book, LWiebe, Aota Chem. Soand., 27 (1973) 2676-2678. R.R.Fraeer, Y.Bresee, Can. J. Chem., 61 (1983j, 576-578. L.B.Krlvdin, G.A.Kalabln, R.N.Beeterenko, B.A.Trofimov, Tetr8hedron Lett., 25 (19841, 4817-4820. G.A.ICalabin,D.F.Kushnarev, R.B.Valeyev, B.A.Trofimov, M.A.Fedotov, Org.Yagn.Heeon., 18 (19821, l-9. G.Y.Kellie, F.G.Riddell, J.Chem.Soc. B, 5 (i971), 1030-1034.