Dimethyldioxirane in organometallic chemistry: A convenient procedure for the decomplexation of arene chromium tricarbonyl compounds

Article abstract of DOI:10.1016/0040-4039(91)80103-D

Arene chromium tricarbonyl complexes 1 react with dimethyldioxirane to give the corresponding arene derivatives 2 in quantitative yields. The reaction is rapid, highly chemoselective and involves an easy manipulation procedure. In addition, the reaction course could be monitored by colour change, thus avoiding the possible further oxidation of substituents linked to the aromatic ring. However, the complex with thioanisole was chemoselectively oxidized with dimethyldioxirane to the corresponding sulfoxide complex.

Full text of DOI:10.1016/0040-4039(91)80103-D

Tetrahedron Letters, Vo132, No.40, lap 5629-5630, 1991
Printed in Great Britain
0040-4039/91 $3 00
Pergamon Presspie
Dimethyldioxirane in Organometallic Chemistry:
A
Convenient Procedure for the Decomplexation of
A r e n e C h r o m i u m Tricarbonyl Compounds
Anna-Maria Lluch, Francisco S~lnchez-Bae£a, Francisco Camps and Angel Messeguer*
Dpt of B~ological Organic Chemistry, CID (CS[C) J. Glrona, 18 08034 B,'u'celona, Spare
Abstract" Arene chromium tncarbonyl complexes 1 react w~th d,mcthyldtoxtrane to give the corresponding arene
d-envattves
2 m quantttatwe yiefd-s "I~e reactmn ,s rapid., highly chemosefcctwe and. involves an easy mantpurauon
procedure. In addluon, the reacuon course couldbe monitored, by colour change, thus avoiding the poss~ble further ox~dataon
oFsubsutuents hn~ed- to the aromatic ring ffowever, the complex with thioam~ofe was chemosefecttvefy ox~d-tzed wftfi
dimethyld,oxtrane to the corresponding sulfoxlde complex
Arene chromium tricarbonyl complexes 1 have become valuable synthehc tooN ra organometalhc chemistry 1 Usually
prepared by the reaction of Cr(CO)6 with an urene derivative, the presence ol the Cr(CO)3 alters the reactwtty of the arene moiety,
thus ma~:lng possible selective transfbrmauous at the aromatic ring or at the hen/yfic pos~t~ons I- Fmaffy, the modified arene
structure is released from the complex by an oxidative process A variety of reagents for performing this decomplexat~on, such as
iodine 2, aqueous Ce (IV) 3 or oxygen and light 4 have been used In this context, we anticipated that dimethyldloxtrane (DMD), a
versatile oxidation reagent that has fbunff a wtffe range ofsyntfieuc appficat~ons §-, could. be assayed lbr such a reaction. This
procedure could be purt~cularly advantageous when other oxidizable groups are present in the arene structure. The present
communication reports our prehmmary results on th~s approach6
Antsofe cbrommm tricarbonyf (fa) was chosen as moffef for optim~zmg the reaction comfiuons l~us, affd-~tion of a solution
of DMD in acetone to a solution of la in the same so~vcnt led to a rapid react,on in wh,ch a progressive decolonzatlon of the crude
reacuon mixture soluUon was accompanied by the concurrent lbrmatlon of a blue-green precipitate When an excess of approximate
3 to 1 molecular equivalents of ox~dat*on reagent had been added, the supcrnatant became colorless and analys~s of the crude reaclaon
mtxture (UV, 1H NMR) showed the complete dccomplexattou ol compound la In hot, it the DMD soluuon ~s added dropwlse, the
reaction course couf6 be easd.y momtore6 as a volumctnc titration hy observation ot tile coiour change A s~mp~e worry-up
procedure led to the isolation of amsole (2a) m quantitative yield 7
Analys~s of the insoluble material revealed that all chromium was present as Cr (Ill) At the same time, assays carried out
absorbing m a Ba(OH)2 solut,on the volatde compounds generated during the decomplexat~on showed that evolved CO2 accounted
for approximately a 2 1 molecular ratio with respect to the starting chromium complex 8 From these results ~t can be suggested
that about two cfiox~rane OXld.ation eqmvafents are used [or tile convcrslon ofC-O figancl~ into L2.32, which would" d.estabfflze tile
arene chrommm complex lead.lng to its rapid decomposition fn tfi~s sense, ox~dation of a CO hgand, to CO2 as first step of the
oxidative decomplexaUon process had been previously postulated 6,9 On the other hand, the lact that all residual chromium was
lbund, as Cr (II0 md.lcated" that DM-D haft also been partiai]3: respond,iSle for tile ox~dhtton o1 chromium zerovafent, probably by
transformation into Cr(ll) However, the overall DMD consumed was not enough to account for both complete CO and Cr
ox~datmn processes, which would mean that some CO had to be evolved during the decomplexatton and that the unstable Cr(II)
species originated would have been rapidly oxidized by atmospheric oxygen
The scope on the use of DMD as decomplexatmg reagent was studied for several repre',entattve examples of arene chromium
tricarbonyl compounds (Figure 1) In all cases, reaction with 3 to 3 2 molecular eqtuvalents of DMD led to the rapid and
quantitative convers*on ot complexes into their corresponthug arcne de:Jvatl\,cs 7 Compounds lb to le represented cases where the
arene dertvauve contained- a substituent susceptible ofoxidhtJon m fi-ont ol DM-D 5- ffowever, DMD showed- a high degree of
5629

5630
chemosoT{ecuvUy towards these comple,:es since the corresponding atone denvanves 2a-e were oNamed, unaT{tered, m quanUtat~ve
ymlds
R 1
R 1
a
b
c
d
c
R I = OCH 3, R 2=17{
R1 =OCTH 3,R 2 = o - C H 2 O t t
RI
= OCH 3'R 2 = m - C H 2 O H
R2
~
Cr(CO)3
~
R 2 -
+
C!oO 3
acetone, 20°C
"
R1 = OCH3, R2 = p -CH2OH
R I = OCT{t3, R2 = OCH2CH=CH
1
2
F~gure t,
Co~vc,rgr.~ft cl~" chcotto~{~oa ~.t-< At'hetty[ co~lLplc',.q,. (Ld-c) gt~o t['tqit* (Ot'Tt.%pO~K{O:lg at'~lg
derna/we> (2a-e) ~aah dU/lethyldlo\l%tnc I0
On tile other hand, in the case el tfnoamsoie chrommm tr icarbonyl compotmd }C~, the fugll reactivity exhibited by DMD in
front of suT{7{ur dcm atrves limited the %ope oi the decompfe\ar~on 7pmc edure Th.-~, addmo~l el 7{ molecular equn,alent of DMD &d
not resuT{t m the oxfdauon e r a CO lrgarld of tThc complex, but m the formatrorJ of the corrv,9or~drag s~ftb,qd¢ complex (1H NMR)
When the acM~t~on of DNID wa,. center, ned c~p t<~ a 4 bred ~r~cdar c~tuo, sc~;ffor<~e c<~ctt~,:,. ~'..u¢ 9,_wt~a~/y de¢otngosed ~c~t a
concom~tartt o2,f&~tfon ol the rclea.,ed suU'oxMe to the sulhme was deter ted
~-n coacT{us'rorh e~ en with the hrnrurtton" dg%r'd',ed above, dec omplexatron ot c hromruru trrcar0onyT{ complexes woo DMD has
s~o~,c~ to be a Ltgtd. el,earl 4ctd cdEvgtR(C(tt, flct3cgd~:rg {c/( the I>l[.(UQgt og ~-~'b~ ¢<lro%/}<l(t(l((l( ~ d{<'(-t(~ deg~v',..0{(vv'v. EKte~M(~tl o~ t~0s
oxdhmve decomp'~¢xauom to other synthcuc .strategies mvoh, rng (}qZ~morud.?bc t,erhcm) i' coruT{~c~cu~d'.; r,, under cgrrer~t study It* our
laboratory
N o t e s ;rod References
l
Coltttaart, ~ P , Hegedus, k S, Noctcm, I R.. Fmke, R G
Umverslty Science Books, Mill Valley, CA , 1987, pp 921-94(1
Se0~'~mdffack, M F . 7{{a,7{. ] r , H 2 . Yoshttagt, N'~ Aa~ C&ere~ So~ 1976 %~, (~,~7-(.~1.~~)
Card, R l , Trakar~ov.,ky, W S , Oq; Che~*g I9g0,45 Z560-25(~5
laotian, G , T,:~F, S, L;.tcotxt, A, Cot~tt~rter, D ; P,rc~card, .~ A~t Che~ Soc t984, l,?0, ~207-27..()8
Foe rev'~ew,'s o~ thc.¢ re.tgeat, sec" a) Ada~m W . Cure{, R, r a w a d s , ~ ,t<~ ( h,.'**¢ a'c~ t98% 22, 205-211 b) Mm'my,
~ ?rmc~gle'~ ariel AT{~Fhcattoa,: (~ O'rgaaotmrts~t~o00 Meta~ Chemistry,
2
3
4
5
)
I
I
0
R. W C~eee~ Re~ D).~9,89, t t S ? - t 2 0 t Fc~ ceccctt -,5'atkct~..~l~91~,.a~,o.t{t. ,,.'c Rc{~c,~>.., 2 , C,tw:ns, F , Me.sscg~aer,
A
Tc,trahedro*t gegg 1997{I,31, S235-5236 and reteret~ces c tted thcreu,
6
?
To our knov,'~edge, the only Irtcraturc 7{~rc'ccd'cr~t oa ~l*c ~gsc, o~ DMD ,'n organomc't,¢~hc ch¢0mstry rs d recent rcgoct or~ file,
WeTpamUoa cot oxornetJs loom ritcmu-m arid nlolyi,dcrmm ¢oruplcxea (Wclklwtcc, S Kn~-hb ~ K lnorg Chem 1991, 20,
1215-1221
[~ a t59t~Ad ,a~Dzrtmc~t, a DMD scffct ,t~ ac,2tc~tte (0 OR-(} tO M, Mt{cc.ty, R \\ , ~,:y'.wa(toaa, R
2853), dr~,.:cl over acuvated mo~ec{~kw s~c~ e,. ,q ,~.), ~.as ,i,:kk.,d cleogw~,~e to a ~ln ,:a- the ¢,~rezsT{~dmg c.hrom~am comF~ex (1,
mmob acetone at cc:,om temper,claw Alter rc'acttor~ was completed (at the hnal point, when to 3 2 molecuhlr
~ Ore Chem 198~, 50", 28.47-
0
!
m
3
equ{~ a~ct~, of DMD I't.~d bc,c'rt added, the se~h{uoa hecoee¢,. ¢ol<~Mc,.,~), ~h~o~t~¢~t~ cow,,~e v< ,~.. chm~e~tcd by hRmuor~ or, be',~er,
by c'~v~tr?lu~at~o~ Evapocauon o~ sc*,h ee~t v~ehffed ¢t rc'q,.hec ,oh<}~ co~t~.e~.ed t~e ..acg~.' ,;k ~*,-at~ ,:>. 2 ~ct h~gh Fu~ty (IH' NMR and
GC)
8
F~*r gr~ at'octroi;re ddermet~ateon o~ 0~c ('02 rcle.~,.ed by the &<'he ( ,:}{~gl(% ~gc~ ,~/~¢rg~.~ge i,use, cdtcgc R,r pr,.Tarat*o.,~ o~ CO2-/ree
DMD so~utlo~s v,c',.x,~ de~.dciped, by' u,,cag a 9~o~7{~hatc bc~ttec .it ,uU: ~ ghc~ ~¢tc&<,du~og5 .d~cto.tcd ,~? C¢5 Kl: D\ID sva)utxons w~ch
exhibited ~.tabd~ty and ovtdauon abtlrty c oe?rgamble t~ t}¢(~v_ c/t<.t~.e0 ¢~.~tL,'~ "#al { ( ' O ; a. ~,~t~,:e
[[a,'um,
10 Complex la was core~mert~a}ly avadab~e ComF;~cvcs l h - l d v~,:cc k~ud~y ~ac&~.wed b5 })c ) M Morc~,(Camgs, F, Co~, 3,
Moret6, M, Pa.g6% LI. Roger..1 Cheett Rc~ , 199(I, 7{810-1R27) (h*mptc'~ Ie w,~', p~c[urcd ~tc¢ordmg to Khand, 7{ U,
E
I
6hem ~oc Cb.em (omw t974. ~26-'~7)
J
[
H
P , Ktetter, C G
I ()rg~utotewtal C& m 1967, 7, 42v- ~',0
A C K N O W L E D G E M E N T Support flora CT{CY F (Grglnt AC, R-,%~-5 ~2 ~, ( l('5 7-Gcnerahtat de Catahmya (Grant QFN-89-
(Recmved m UK 14 June 1991)