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Inversion of Configuration in the Brornination of f invlie Plercurialst
cn,q.rtr,ns P. crspy,x GeoRGr: ),I. wunosioEs, AND,Inel I(unru
Depariments o.f Chcmi,strtl, (.iniuersitrl of Wisconsin, Madison, Wiscon,sut s5706.
an'rl XIassachrisells Irtsti.ttttc of Technology, Camb,rirlgc, Massachusetts 0ZI;i:t
Recebed March 28, I97S
'fhe brornination of cis- and trans'l-propenvl- and 2-butenylmereurr'(Il) bromide irr earbon disulfide ocellrs
rvith predonrinant inversion of configrtratirin at the double bond. The rate of bromination of lrans-Lbrrten'lntercrrr'.v(ll)
bromide in ctrrbon disrrlfide is 7i times as fast as that of n-propylmererrry(Il)
'fhe
bromide. ot>
sc'rved ittversiotr of configuralion is consistent, v'ith a trans addition of hromine to the earbon--carbon double bonci
of the vinYlie merctirials f ollo'*'ed bl' a trans elimination of rnereurv(II ) bromide. I n eontrast to the re,srlts in earlron
tlisrtlfide, the bromination ,,i thL vin-"-lir: mercurials talies place s,ith retention of r:onfiquration in nvrirljne.
i\ sturi.r' of the bromination of cis- and trans_2_
lrriton.r'l- lncl l-propent'lntereury(II) hromides (com-
I)()lrrl(lr l, 2. 3, and 4) in earbon disrrlfirlc n'a-s initiated
jrr ln ltlr'nr1rt to goncrAtr. frr,r'propcnyl raclicals of
Iilri'nrr str'1p6plgmi-qtrr, ar)d to irrvcstigato tlrr.ir storeo-
.ll.rri..l fate.2 A fre.-radical p:rthrva1, for th. brotnirrrttiorr
of thcse compounds in carbon disulfirlc rvas
).)
tla,.
HsBr |1 n \a\ y^.:
n *
HoRr'
(r-*
(_..\n, I -.'.,,,
+ t'i., :;).1
t\:,/
I
[{gBl HeBr HgBr HcBI'
2
rrrrtiliprrlr'rl at thc riutset, sinee ,]cn-qen had shou-n that
1lrr' f n'rrrrririation of c'ither c?s- or trarts-4-mcthvlcvclolr,'rvllrl{,1'('llr\
(l I) lt16nrids in dr,gasscd r.arlrlrr clisrrlfirlr-,
irr',,,lut','rl 1 Iio serno ratio of czs- and li'aris-l-brorno-4-
rrrr'lrlicli'lr,lr.x:rnc and had intorprerted tho lt.rs-s of
of stcri'or'ircmistrv jn torms
'l'lrr' of a frpr'-radieal rr.action.a
lrrissilrilit.r' .f an aitr'rnativc pathri-a3' invrilving
r"t'tcirli,rrr ,f stcrcr)chcmistrf in thr-' bromination of the
vinvlie merctrrials \\'as also r:onsidcred, siltec, .l(,rlrr':;j'
had shor,rn that the bromination of the isrimnrir rlrr,1h.r'lcyelohexvl
me'reurials in methano] procot'ds s-ith x;r,;
retention of stereoehemistry. Here, \\-e rc'po11 tlri.
surprising fincling that hromination of l-propen.r'l ::nri
2-butcn5rl mercurials leads to propenyl and hrrfcnr,.l
bromides of inverted ste'reoehemistrv.a
Results
Synthesis and Stereochemistry of Vinylic Mercurials.
-cz.s- and lrazrs-l -propen.yl- und 2-butenvlmercun'tll)
'l) >rr1,1rorterl in Jrart lry tIe National Science I:ounriation. (irant,s Gp-
18.)l{i )i rinrl (iI)-2018.
t' [-. .\. Sr.ge. in ",se]ective Organie Transformations,"
'l'lrl
Vol. II, IJ. S.
rganljarl, ljd., \\'iie.r', Nerv York, N, l-., 1gll, p 28g.
r.i) I'. Il.,lensen and L. H. Gale, J. Amer. Chem. Soc., g2, 14g (1960).
(4) -\ lthough the ciremistry of cis- and f ran s- l-pronenvlmercrrry (I I r h:rmides
has been sturlied in cietaii.s the halogenaiion of these compounrl:-r hri:,
not been reported.
(5) '\. N. Nesmeyanov, ,\. L. IJorisov. and N. V. Nor-ikovn. lzr'. :lkt:rl.
.\azfr SS.SR, Otrl. Khrrn. Nauk. 1216 (l9b9): Bull. Acad. ^lci. j'.:S,Sl?. /)rr,
Chem. Sci., I 174 (1959).

BRolriuarroN
oF VrNyLrc N,InncuRrALS
J. Org. Cltem., Vol. 38, Na. 1g, i!)'i:l 34A7
Trans, 4
'Irans, L). 00 trI
4 NIeOH, air, 0. 02 tI
BnourNatroN oF Vrlryr,rc
Compd
Cis, 3
Trans, 4
Cis, I
Trans, 2
Cis, 3
Trans, 4
Conditions
Pyridine, air, 0. 035 Xt
Pyridine, air, 0.035 X,t
CSz, air, 0.05 X't
CSr, air, 0.05 ,\I
CSz, air, 0.03 llt
CSz, air, 0.06 ,11
Tanr,n I
N{nncuuar,s rru PyHrDrNr,l ,\Nr)(l.rnnox f )r:;ur,r'rnn
RIIgIlr, mmol
llrr, mmol
025 025
0.25 A 2it
0.11 0.1I
0.10 0.10
0.27 0 27
0.20 0. 20
0.12 0.t2
0.02 0 02
Vinyl bromid
.-."---Cis: trane-- -\
99. 6
,J.{)
2l .8
/.).;)
11.6
92.9
9l 8
778
(.) 4
9r.9
782
2(i. it
884
7.r
s.2
22.',z
l-i el, I .
1tj
1) I
f(){}
tt):
br.nricle \vcre synthesizcd stercospecificalll' by reaetion Bromination of vinylic Mercurials in carbon J-ii,irifide.
-Thc br'min:rti'. 'f th. vinl,lir: n):,r(,llr-irri, !. 2.
of m.reury(II) brclmide rvith thc corresponcting vinylic
lithium re.gcnts0 preprired from stcru'chirmically
pur. r'i.r'lic bromiders. 'rhe 3, and 4 in clrrbrln rlisull'irlt' urrs hrghly sir.rr,,;,:1.i1,,,rr. 1,
isomcrie l-llrop.nyl- arrd but gllv(r vinVl tlrontidr.s itlrving otrl1){r;r1,. ,.1r,1.r,r,-
?-butcnr.lI ithiuni r(.ag('rlts had becn preparerl prcvi.,,usly ehemistry from thc nr.rt:ttrv r"ornpruirris fr,rr,, .,11,,.j;
anrl dlrnonstrated to bc conliguraticnallr. stalrlc, orrce tlrery \\'()re dc,rivecl (-l'.rblr, l). Simti:ir rr,.r:,tfiirni.d.'-e
Tht' stt'r.'ch..rist^' .,i
'f r:rs- a.d rrans-rr)r'ol){,n\"ltnor(jrlr.\'(II)
brornidt,, t arrcl 2, u-as originallv r.r-lriclr nornrrlll rct:rrrls frr,r'-ratlir,lrl;rr,trrrii:r r
obtaint'd itt rJeglrssccl solutirins or rn 1lir, p1",,5.1.y;r r ,:i .,, i,
rissig;ri'rl h.,. Ncsmevano\.;
:; ,, ,.,
,rr thr, blsis of tirr: niethocl moreltrials.'r {}1onlirrlrtir\It (rf 4 irr nir,tir;i11r,i ;,l ,,
'f
: ,
sr nthr,si-* from the corrcsp,ndilrg lithiunr reagents. lrretiorrrirrarrtlv thc vinrlic bronrii1
.J.iis.lllc lras r.cently demonstnrt.rl thlrt ero- anrl, endc,- fisuratiolt.
J*rrrrrll'r.t'Imagne-qium br'rnidt' react *'ith m.rcurv (II;
iirrnrid. to giv. the corr.sllo'ding ark'lnr.rcur1,.(II)
ltr,,niirics li'ith compk'tc
'flrl
rctcrrtiorr
IJr
of confiquration.
,'/
s1r'roochemistrv of cli-crs- :rncl
nr'
cli-1raas-plopcnvl_
/-\
,/\
nl('rcllr\-(lI), 5 and 6, rcspectiv.l.l,, hlrs lJ(,(,n assigned
tttrambigurtu-*l)' it.y nnrr. I I
t igFlr r: /
1 i,li:,
4
The assig.m('nt rif ste*roclrt'rnistr' ,f .s- and rrons-
2-brrt.n1'lmcrcurl'(II) brrmid. is bas.d rin
IJr'
l'ir
the methocl
/
rf svlrtlrcsis
,._.* -J
rrrrl on thc nnrr slrcrrtnr ,rf
r )
tht, eompounds.
/-,,
()ri-ing /\
t, cl.sirir,lding br, thr: r,is nrr,r.r,urf. atom,r the
Hgllr
Br'
.ii,'nrieril shift of thc vinl'l prot,rr 11,
.is to mr,rcurv in 3
3 ss;'i
is o 5.5{i ri'irilo tlie ch

3408 ,l . Org. Chem"., I:oL g,9, ;Vo. ig, jgis
Regtsirl
rc,.
:ljJii.l-11:.i_ I
182;7-68-6
f',rnr,r: fI
lir.i,r.irvi. Ii.r.rns or. Bnourx.\TroN rN
C:\Rlr(iN l)tsr,'lr,tlr..,r \lr lryRIDr\ir.;
./tt.^'\-r'
-.-1-.llg
Coml:,1
Hgllr
Rr
Reiutive
rate in (,'S:r
Relative
rate in
Cr[IrN
l.(.) I 0
(4\ 2.2 : 4
0 0?9 0.9
'rl r'.rrrligllrltio]l ,l)s.rtr-r'(i in thc brornination of th(,
vinyiic nrcrcrrrials is riot (.onll)lrtiblr- rvitir t'i1h,,r of thc
t"r-o abrv. mer:hanisms ancl mll-qt hc, occurring ir,r- a
diflcront nrcc,iurrristit, pltirt-ztr..
'f hr' lrrr:rl()nliu,ilrrt irrvr,rsion'f r:.nri gurat ion clb-"r:n'r,cl
rn r-'lrlr,,rr rlisrrlfid.{'{,'rin bcst }.,r'L,xplain('d b1,- a trans aclrlitilrr
,i' lrroniinc t, tiie r,llbr')r]-curbrln cloublc br,ncl
rrt flir'I'inllic mcrcrtrini toilori'r,d lr.r. a trans olinrina_
rirrrr r.rt' rrrlrcur.r'fII) irronriclt' Ir',rrn
'f
tlie rcsulting aclcirit,t.
l,i- aritlil i,rr i'linrinatiorr nrt,r,lirrrrisnr irnlilics tirat tlic
lllll'irirr -r.lrt'l)r,rr rioublr ltorrrl i, rn()r(, rcaetive torva"rti
bon-r:arbott tliiul-lir' l,'i-ind of 1*ltcxc!,r. :r; 'l f i, r,... ;,,..r
reilcti\'0 trrultrci llri)l)iill(t iharr f irl n:rrii,i,F ri :.:,,,, i,, : .,
of l-pro1,'!"lnrcrr.rrr.\'iIl\ hrilri-il{lr, ilrr, 1.,\f , i,,i1,-: , ,
havo tltc lArnc rol;ttir.i' I't,lctir.if .i- 1ri'.r-1",1.: 1 r,,r,
P)'ridint: sllgg{.:tt ing rr: inr.rlllsed r(,iat lr-i. r.r lr.: i
thc carb,')lI-nlrrcrrr-i. bi;ncJ in Jx-rirlil;r.
r:::,,i,, -, 1. .
reiatir-r' t"C:tr'livit.i- ,,f liit,'s-l?-ilrrtr't]-. jt:,, ' :, :,.;
mirlr' ('ontptr,'ll ',1'itii l-i,r,i,.r1 ., j;1 r,!^r,lr...ri.i :: . ,
,rn g,ting frlnr clr-i,,,rr rlisiijfi,-il'rllI)\-t'r, j;r r.
Th,t invlrsir-rn rif i,ril;figttila1 ir-rn l'(!l)!r,*tlri ir,,.r . 1,,:
bromjnation in (,arl)ori disrrjfidt ,r{' li;,, i;;,.,ii,. 1r,,..
r:urials l. 2, 3. rnil 4 is srrrnrisrnq, srri,i ,, !i,.. . .
It'S|lf:']t nIt tlii'h;ri,'g,,i:.rti rp ,,f \.i:ti': :,. - -
rir'ri irttt irr titt, r,'::i,rrrr.li qrrlitl)s iii \1r. 11 ,..,, , .i
lieutr''r' hld yrrr,r-ir,,1si.f i;rrlii:;it,.rii t1,,"" i,.,. .,,,.,
/)CCl-lrrcd citht,i l,l, rt tirilt" C:.Ili{ri i;, I . :
f'()r}lpl{'t('rr,tr'lltirl1ir'i..tr,r.'.,,r.hi'i!li..tii''.;"]..
il(ilist('!'('f rsltccifil i'r',',,-.:^lriir,:ti tnt.r:lr;:1ir. r,. r': 'i11
Sr'rl;!tinn t'f r-iiil'ii, i),i l:.:r'i;:i:. iS rr..r-. ,,:,
li{i1 ilr pllar sr,l i.,.rr t :- r.} iir i ;,r,1:st q,11,1.11;;;11,r.:r,.
srilt'r'ttts. l',sltrng'li r , ri f 'r,,',r,'1 ,trti, iri i
r('i(,Ilti()n rir.li,r-, ,,,i,,.,::,f," :
;:i, l1ii,
i.rf CfS- anrJ 1rg;;.r-.1;:i,,.,,'']:rt,,i,,l:l-i' li : ..
ox8.ne,la the i,,riili'trr,,1r rrr : t.. ;.ti,l j'r.i,..
('Fi, f{ C rner(ltlr)'(II ) ,'i,ir,r'i,J,,
B. i{ r.l 'tr
tr: ri!;,r:lrltrr,.!, rlii;": ,' :
fcrtnlltttitlr'.rt' -rlri! tlr,
il:* I{\j-----r'l -t{ril I'irrl,;t; rriirti ,;.
r, 'H -
r i i,,,-s /-f
ia;- !+
/
,,
stt'rvlmerettr.r'tli; lrr',ri;qi{, i:, lri't!;:,
Hgtsr B; HgBl it (.t{ sttlf6ridr'.it Irl r.,,lrtrtsi. rltr {,{itri{, !!.,,:"r..
tnlits i'in.r'lrc ii;rli,i, -. i., ,,lrtliitr'ri ilr f i,. : r :
iirrrmirro than is iritlitilitiott r,f ,"r'..r.- lt::,1 l,'i-,;:,r-ij-'i r -,'], , , ,
r clrrllr)n n-l{,r(,ilrt. bonrl. If t}re, r,:icli_
iilrr r'iirrrinrrtion rr-rtc,iulnrr-nL i. r,,rrrr',.t. l liclr. l)\,
It'ririr' itr r,;rfhr,i) 11,f i.:1r,1;l,rli,ir, i,i.
oxtorrsl()lt.
()It(' n ottl

BnourNarroN or VlNyr,rc N{nncuRrAr,s
J. Org. ('licni,., \'o1..98, l"r. f !). t,::. ,.
1 l iii)
T.tnr,n III
Coltpi;rrrrox Rracrt()NS FOR BRoutrr; ts C.,rrrnox I)rst.'lrlnr,; ,rNrr I)yrrnrrNr,l
-Irritial concentrations of reactants, 102 lf--- - , -------_----tlolar ratio oi lrrorluct.q-
Solvent
gRr
-)
llgl3r
CSz
0. 16 0.56
CSr
4.1
r=
C'sH;N 7.6
5. ,)
CsII;N
8.3 9..ir
" I)eterrninedby disappe&rance of 1-hexene.
Brt
0.062
2.2
7.1
10.4
j lJr,rmo
I lru tent,
| .4:
294
I
) ''-
ii
Ilr
t1t
]-lr
i
i..-.,,--.
t^)
1 {}
I {)
I {} i l|
ti,n .f brominc to th. r:lrrbon--carborr dorrb]r' borrcl to
git'r' ln isolatcd intcrnrediat. dibronriri(,, ri'hich then
ulltl{rrgo('s a ba-se-catall-zt,d trans ciirnirration. T}re
Ilr ()BLr )
{'rrr})(,rr }rorr)n bond is rt'lirtivr'lf inert to bronrinr,20 and
ii is rr,,t surJ;rising tiuit thc carlron--carbon rloublr' boncl
r< rrit:rckcd prr'fercntialll in r.invl boron (,onrJ)oun(ls.
[J1r,'.r'il ]i ]rr-* rlclrrtlr.- s]rorvrr that t lre clibronritlt' prr'-
I):rr{,,.1 frorrt a l'in1.ltit}rllrI(. tlt'r:onrposcs ilt tlrr, 1-lrt,sencc
of l;ltsr'lrv rt tnins c'lirninlrtirrn to gir.r'lr virrr-l ltromicle
of irrvortcrl t,orrfigrrnttirtrr; hr)\\'r,.,-t,r, thcrrn:il tlt,r,onrpr;sitirin
of th(' dibronridt' irr larlron tt,trar:irloridr: pro-
(','t,rlt'd lr"v a c,is t'limirration t, git.('u \-invl brt;mide of
tlir srinlr collfiguration as tirc r-in.r'll;r.,ran(,.
Experimental
Section
t rens-2-Blttenybnercury(II i Bromide. --\lt,r.rrrr..(
II r rirrnricie
(i7 0 g, ().1).17 lrrol ) tvts rLtlrletl 1o an r,thr,r -r,lrrllrrrlrf/rrrn..-J-
lrritt'nvllithiurrr6 trrrepared fr,nr lrnns-i-trr'nro-2-irrrlr'ner ((i.4
'firc s.
0.{i17 niol ). relrction tnixtrrre wtq pr,rrrcrl inl() $.rr1er an(l
the t'tltet' lrtr-er \\'lrr\ scplrnrterl. u lrsherl q'it lr \\.rrt('r, dlie

3410 {.)r't. ('ltr.:t,.. l'oi. J8. ,Vt,. ig, t9)S
ij.-'r';;r,l'\r'{,lt,i';rir'rll:Llt."tl iisiltg tltr,'f, r}lr;,,r'irr;1 Iorttulii
, ;r('('{):lli1,liiill't,tri','i irt rrril i:ll rLtrrl iirtiil r','11r,q.1ti r:itl(}I!>
dl
ir: .1 -- lr -1,,
in /i - irr /1,;
i l.A.sry Wnlrnsr
DES, ,i :i ii lrl;-ii"r.t
Registry Nri. i, f;;:.1;-"tr1i-,'i : 2, il7i7-+tr-: 3, ;i,l'.;1. .,-':;
r
4, 4(i7xJ-;l\*i. lr,i,,.r'i!,'r : I I : trritr,irJu. ;:h1, i; ": :'rrr.',s--l-r)i. .l
lrthir.trn. jt')-1.+-x(i-; ',. 2-iril1-i'rrlilit !:rr',-..'lqri l.l -'.:,, l ;',,"' j
prrrlrelri'llttliirtnr. fi.i\{:-il-7. ,':.'-i ;.'r,i}:(i'r:'. i;iliirtrtr. (i:;\ir'.-
'.
I,r i omirre, ? 7?tl-{i,i-ti
q
?
4
?
I
*
l
I
I
t
:
I.