Syntheses using electrochemically generated cobaltocene or cobaltocene anion

Totdmdron latterano. 11, pp a75 - 078, 1975. Per#uollPrW8.

Labonatotiine de Polanogmphh (Received

in UK 21 Jumry

Oa.gan.ique,l%cu&Z

ti

PrInted In Weat Eritdn.

Sciences, 21000

19751 looepted for publication

VTJON (FWICQ)

5 lbhruary1975)

theex.i.stenceofwhichwaslateramfinnedbyG8iger4.

OR'

-R"

e

e_

eR' co+ -RI'

-

&R"

1' =

&_R"

-2' =

3' =

I

(1)

~rthe~~mrpound(~';R=R'=H)thehal~~arere9pectively- 1.20 ad - 1.86 V (E.C.S.)in 30 % e&anol-wabr solutionsand - 0.77 and - 1.73 V (E.C.S.)in 0,l M 'C4H&WZ104 dimthylfommide. klewishtoreportsaneexarplesshowingtheadvantagesofusingelectrochanicatly~ inthecobaltocEnese.ries.

neratedoAallzxeneorccbaltocEneanion8for~

S-8

rthasbeensbm

that

-~cyc-

1o3baltoycl~-oanbe

prepamdbythemactionofzmamyl

orallqlhalideFxwithahaltocene.Fran~desofco-

baltoaz¶e,alend.eoft9lepmalct$

andonermleoftheozbalticinimsaltarefod. R _.

k+

H

RX

+e

t

,

I

DMF' t-O,77

to

875

-1,2V ECS)

(III)

876

NO.

(a)Cobal+zxxns,bshg~unstablemingto

disadmnm:

Thisreactim~~

11

itsoxidabi~ty,isdifficulttpprepareandto~ipilate; it is rmmxciallyavailablebut expensive.(a)Theyleldofths ?zeacumbasadoncobal~isneQssarilylimitedto5o%. wehave

carriedautreactiln

IIuslngazbaltocenegsnsratedbyel~lysiaoftheco-

lx¶lt.icirhnsalt~ heacual III).1 is easy to prepareand very stable; the yield is practicdlly100%,sincethecobdlticiniunsdlt~~isreeledralyzeduntilccmpletion0fthereac tia~.motkradvantageisthegreabxcvelocityoftheel ectmhnical~swhenthechemical~isslCkl(88etahle).'Ihlsfeaturecapllnabablybe~llkinedbythefactthatthe mxeslowlybecauseofthsel~regeneration. aDmentrati~0fcdJal~~

fb Substitmt

R

4C CH2Br

cH2%%

-%%

95 G20°C)

96 CiCf’C)

98 00°C)

47,55 GOT)

446(4cPC)

457c?0°C) 45*Mo0q

&-Cal

2 h.

7 h.

1 h.

5 h.

cbelnlcal

mrm.

50 h.

1 h.

5 h.

CCl3

90 (2oW

Tims

Prepmatialsstartlngfrantheinicn. Even

HOI-e

inwjng

synthetic

possm.lities

assbwnforexzmplebythefolluwingreacUm:

are offeredby o3bsllzocere

anial

a,,

x0. 11

e?7 q0~tadi~labaltc&xxyq0~~lsratherrathereandwasanverted

~inbjtutnthemethylesterSbytheacticnofEthyliodide9.Bwaslden~fiedbyoentesimal [n.m.r, CllCl3,6 p.p.m. : 2.80 I

%$analyeiSdbyitSSpCt.Ed~.

4.81 C5,H5 ; 5.31 Hi, ~~1Ci.r. v 2

1736 an-'

; 3.43 C)5J1 ;

(a)].

co2-

A,

H

CH31 Li+

*

(V)

DMF

zb 6 =

5 =

Electrocheniealoxidatim of the ester 0 (E = + O.O5V, 40% ethatxAB, the~cxbal~

pH3) gave

salt~inpooryields~1O%);the~0f~with

C02CH3

dr

eCo2CH3 (C6H5j3CBF4 c loo %

(VI)

078

1.

Ho. 11

N. EL b¶JRR,R. D?ml?D and E. LwIFm,

3. A.A. VICE&

Co&tat.

h%.h.

Ckm.

4. W.E. GEIGER, J. Amen. Chern.Sot., 5. G.E. HEmmcH 6. G.E. ImBEmcR,

J. Oa@wom&td. Chm., 47, C 13 (1973)

J. AWJL. Ghan. Sac.,

2. J.A. PA& and G. m,

COfmn.,

l4, 6149 (1952)

30, 952

(1963)

!%:I 2632 (1974)

and E. BADm, 1. Ongunometae. Chem., g,

301 (1969)

G. GRErS and H.F. HEIL, 1. Oqanome.taL. Chem., 2,

7.' M.L.H. GEtEEN, L. PFA!.lT and G. ~~~m?sx, 8. G.E. HEEBERICH,E.BAUERandJ.

J. Ciwm. Sot.,

XHQSZER,

J. 0aganome.ta.t. Chew, &

9. s. YcNmA, z. YosHmA and K. FuUII, Kogyo Kagaku Zuuhi, f& l0. J.E. SkIEATSand M.D. RADSCS, J. 0%.

723 (1970)

3753 (1959)

Chem., 35, 3245 (1970)

11. N. Es MJRR and R. IIABAW, J. [email protected]. Chem., &

445 (1969)

641 (1966)

C 82 (1972)