The synthesis, structure and reactivity of aldehyde substituted η3-allylic complexes of molybdenum

Ž

.

Journal of Organometallic Chemistry 550 1998 267–282

The synthesis, structure and reactivity of aldehyde substituted h³-allylic

1

complexes of molybdenum

)

Claire J. Beddows, Matthew R. Box, Christopher Butters, Nicholas Carr, Michael Green ,

Monika Kursawe, Mary F. Mahon

School of Chemistry, UniÕersity of Bath, ClaÕerton Down, Bath BA2 7AY, UK

Received 24 February 1997

Abstract

5

w

Ž

. Ž . Ž

.xw

2

x Ž

.

Reaction of cis- Mo NCMe CO h -L BF₄LsC₅H₅or C₅Me₅with 1-acetoxybuta-1,3-diene gives the cationic complexes

2

.²4Ž . Ž

.xw

x

4

5

w

Ä

Ž

Mo h -syn-s-cis-CH₂CHCHCH OAc CO h -L BF₄, which, on reaction with aqueous NaHCO₃rCH₂Cl₂, afford good yields of the

3

5

w

Ä

Ž

.4Ž . Ž

.x

.

Ž

.

Ž

.x

anti-aldehyde substituted complexes Mo h -exo-anti-CH₂CHCH CHO CO h -L 2 LsC₅Me₅, 4 LsC₅H₅. The correspond-

2

ing h⁵-indenyl substituted complex 5 was prepared by protonation HBF₄POEt₂of Mo h -C₃H₅CO h -C₉H₇followed by

3

5

Ž

w

Ž

.Ž . Ž

.x

2

Ž

.

Ž

.

addition of CH₂5CHCH5CH OAc and hydrolysis aq. NaHCO₃rCH₂Cl₂. An X-ray crystallographic study of complex 2 confirmed

the structure and showed that there is a contribution from a zwitterionic form involving donation of electron density from the

molybdenum to the aldehyde carbonyl group. Treatment of 2 and 4, in methanol solution, with NaBH₄afforded the alcohols

3

5

w

Ä

Ž

.4Ž . Ž

.x w

Ž

.

Ž

.x

Ž

.

Mo h -exo-anti-CH₂CHCHCH₂OH CO h -L

6

LsC₅H₅, 8 LsC₅Me₅; however, prolonged 30 h reaction with

2

3

5

w

Ä

Ž

.4Ž . Ž

NaBH₄rMeOH surprisingly gave good yields of the methoxy-substituted complexes Mo h -exo-anti-CH₂CHCHCH₂OMe CO h -

2

.x w

Ž

.

Ž

.x

L

7 LsC₅H₅, 9 LsC₅Me₅, the structure of 7 being confirmed by single crystal X-ray crystallography. This methoxylation

reaction can be explained by coordination of the hydroxyl group present in 6 and 8 onto B₂H₆to form the potential leaving group

y

4

5

HOBH₃, which on ionisation affords Mo h -exo-buta-1-3-diene CO h -L

which is captured by reaction with OMe^y. Complex 8 is

w

Ž

.Ž . Ž

.x^q

2

4

w

Ä

also formed in good yield on reaction of 2 with HBF₄POEt₂followed by treatment of the resulting cation Mo h -exo-s-cis-syn-

CH₂CHCHCH OH CO h -C₅Me₅BF₄with Na BH₃CN . Reaction of 4 with the Grignard reagents MeMgI, EtMgBr or PhMgCl

afforded moderate yields of the alcohols Mo h -exo-anti-CH₂CHCHCH OH R CO h -C₅H₅

5

Ž

.4Ž . Ž

.xw

x

w

x

2

3

5

w

Ä

Ž

. 4Ž . Ž

.x w

Ž

.

Ž

.

11 RsMe , 12 RsEt , 13

2

Ž

w

.x

RsPh . Similarly, treatment of 2 with MeLi gave the corresponding alcohol 14. An attempt to carry out the Oppenauer oxidation

X

3

Ž

.

x

w

Ä

Al OPr ₃rMe₂CO of 11 resulted in an elimination reaction and the formation of the h -s-pentadienyl complex Mo h -exo-anti-

5

Ž

.4Ž . Ž

.x

CH₂CHCH CHCH₂CO h -C₅H₅, which was structurally identified by X-ray crystallography. Interestingly, oxidation of 6 with

2

n

w

xw

x

w

xw

x

Bu₄N RuO₄rmorpholine-N-oxide affords the aldehyde complex, 4 in good yield. Finally, reaction of 11 with NO BF₄followed by

addition of Na₂CO₃affords the fur-3-ene complex Mo h -

2

5

w

Ä

Ž . 4Ž .Ž .Ž

.x

H Me CO NO h -C₅H₅. q 1998 Elsevier Science

S.A.

Keywords: Molybdenum; h³-Allyl; X-ray diffraction

1. Introduction

molecules, that is with the exception of recent work by

w x

Vong et al. 4 and Liu et al. 5 , which has focused on

The use of transition metal fragments to control and

direct chemical transformations at coordinated organic

centres is an important area of study, and while consid-

erable progress has been made with reactions based on

the reactivity of syn-substituted functional groups, e.g.,

3

5

w

Ä

Ž

w x

.

4

Ž

. Ž

.x

Mo h -syn-CH₂CHCH CHO CO h -C₅H₅. We

have previously shown 6 that treatment of the labile

bis acetonitrile complexes Mo NCMe CO h -

2

5

Ž

xw

.

w

Ž

. Ž

2

3

5

w

Ä

.Ž . Ž

.

x

w

x

the Mo h -allyl CO h -C₅H₅system 1–3 , these

2

.

x

Ž

.

L BF₄LsC₅Me₅or C₉H₇with the 1-trimethyl-

silyloxybuta-1,3-dienes Me₃SiOCH5CR¹CH5CHR²

studies have been largely concerned with alicyclic

1

2

1

2

1

2

Ž

.

R 5R 5H; R sMe, R sH; R sH, R sMe re-

sults in initial coordination of the 1,3-diene followed by

a rapid fluoride anion initiated desilylation reaction

resulting in the formation of syn and anti 4-oxo-

)

Corresponding author.

¹Dedicated to Professor Ken Wade on the occasion of his 65th

birthday.

0022-328X

r

98

r

(

)

268

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

3

w

Ä

¹Ž

.4

functionalised allyls Mo h -CH ₂CHCR CHO -

5

Ž

. Ž

.

x

w

x

CO h -L . Having previously 6,7 studied the pro-

2

tonation of these complexes and gained insight from our

investigations, we believed that it might be possible to

devise a selective synthetic pathway to the anti-al-

dehyde substituted systems, the chemistry of which has

not been explored. In this paper, we describe the suc-

cessful development of our ideas and a preliminary

study of reactivity.

2. Results and discussion

w

x

Ž

.

Ž .

In studying the protonation of the syn- and anti-4-

Scheme 2. M sMo CO ₂L,Lsh-C₅H₅or h-C₅Me₅; i -Trimeth-

3

ylsilyloxybuta-1,3-diene.

w

Ä

oxo-functionalised allyls Mo h -CH ₂CHCH-

5

Ž

.

4

Ž

. Ž

.x

CHO CO h -C₅H₅prepared from 1-trimethyl-

2

w x

silyloxy-1,3-dienes, it was shown 6 , as summarised in

Scheme 1, that the syn-isomer affords, under kinetic

control, a 1-hydroxy-substituted h⁴-s-trans-1,3-diene,

which isomerises into the corresponding 1-hydroxy-sub-

stituted h⁴-s-cis-1,3-diene complex at room tempera-

ture. When the hydroxy-cis-1,3-diene cation is deproto-

nated with triethylamine, the anti-aldehyde substituted

system is then formed selectively. Initially, it was

thought that such a reaction sequence could be adapted

to provide a procedure for the selective synthesis of the

anti-aldehyde systems, but, as the combined yields of

the syn- and anti-aldehyde complexes are relatively

low, it was realised that an alternative synthetic strategy

was desirable. Consideration of the detailed steps

Ž

.

Scheme 2 involved in the desilylation reaction se-

quence surrounding the formation of the syn- and anti-

aldehyde substituted complexes, suggested a possible

new approach. Thus, if it is assumed that the kinetic

product of the reaction of the 1-trimethylsilyloxybuta-

Ž

.

1,3-diene with a cationic bis acetonitrile complex is a

h⁴-s-trans-1,3-diene complex then the syn-aldehyde

substituted h³-allyl must be formed by a rapid desilyla-

tion reaction. If the corresponding anti-aldehyde substi-

tuted system is to be formed then a change in the

bonding mode of the 1,3-diene from h⁴-s-trans to

h⁴-s-cis must compete effectively with the desilylation

of the h⁴-s-trans-trimethylsilyloxy-1,3-diene cation.

This suggested that if the anti-aldehyde substituted

h³-allyl complex was to be formed selectively, then it

would be necessary to use an oxy-substituent on the

1,3-diene, which is less labile than the Me₃SiO system,

thus allowing time for complete trans to cis-isomerisa-

tion, which is necessary to establish the correct C₄

geometry for formation of the anti-aldehyde. In princi-

Ž

.

ple, see Scheme 3 this could be achieved by first

ŽŽ .

Ž .

Ž

.

Ž .

Ž

.Ž

.

Scheme 1. i sHBF₄POEt₂; ii Et₃N; iii R-Temp .

Scheme 3. i NaHCO₃aq. pH 8.5 , CH₂Cl₂.

(

)

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

269

Table 1

w x

coordinating

8

1-acetoxybuta-1,3-diene onto

a

4

5

Ž

.

w

Ž

. Ž

.

x^q

Fractional atomic coordinates 1=10 for 2

Mo CO h -C₅Me₅

fragment, it being assumed that

2

the initially formed h⁴-s-trans-bonded adduct would

isomerise at room temperature into the required h⁴-s-

cis-bonded isomer. Nucleophilic attack by hydroxide

anion on the resulting acetoxy carbonyl carbon of the

coordinated 1-acetoxybuta-1,3-diene would then be ex-

pected to lead to the selective formation of the required

anti-aldehyde complex. It was recognised that this ap-

proach, if successful, might, form the basis of a future

kinetic enantioselective resolution by utilisation of an

Atom

x

y

z

Ž .

y55 1

Ž .

1486 1

2031 11

1168 36

1157 12

Ž .

2565 1

1474 10

Mo 1

Ž .

Ž

.

Ž

.

Ž

.

O 1

y2479 10

X

Ž .

Ž

Ž .

O 1

y1910 28

825 21

Ž .

Ž

O 2

y1897 12

4262 8

X

Ž

.

Ž

.

O 2

y2491 24

1901 37

3655 30

643 7

4343 27

Ž .

3417 5

2578 5

Ž .

1734 5

2063 5

Ž .

3081 5

4445 6

2573 8

710 6

Ž .

1420 7

3727 8

1889 10

1406 39

3648 13

3223 24

3349 9

2420 10

Ž .

1533 8

1413 12

Ž .

Ž

.

Ž .

O 3

y1768 11

y683 12

X

Ž

O 3

y1787 33

y677 39

Ž .

C 1

899 6

3130 7

Ž .

C 2

Ž .

287 6

872 6

1846 6

1845 6

624 9

y693 8

597 8

3625 6

3139 7

2342 7

2348 7

3471 9

4636 8

3477 9

1719 9

1708 9

1759 13

1240 43

1273 15

Ž .

C 3

C 4

C 5

esterase such as PLE to hydrolyse the acetoxy group.

Ž .

5

w

Ž

. Ž . Ž

.

xw

x

Treatment of Mo NCMe CO h -C₅Me₅BF₄

Ž .

2

Ž

2

.

Ž .

with 1-acetoxybuta-1,3 diene CH₂Cl₂,4d resulted in

C 6

Ž .

C 7

C 8

C 9

Ž

.

the formation 71% yield of the cationic green crys-

Ž .

C 10

C 11

C 12

C 13

C 14

C 15

C 16

Ž .

4

w

Ä

.

talline complex Mo h -s-cis-CH ₂5CHCH5CH-

Ž .

2769 8

2781 8

5

Ž

.

4

Ž

. Ž

xw

x

OAc CO h -C₅Me₅BF₄1, characterised by ele-

2

Ž

.

Ž .

mental analysis, IR and NMR spectroscopy. The IR

spectrum showed two terminal carbonyl bands at 2053

and 2006 cm^y1, typical of a cationic complex, along

Ž

.

Ž

.

Ž .

Ž

.

y1582 15

X

Ž

.

Ž

y1238 34

Ž

.

Ž

y1251 13

X

Ž

.

Ž

with a band at 1759 cm^y1due to the CH₃C O O group.

y1557 56

1735 51

Ž .

Ž

.

Ž

.

Ž .

225 11

y444 9

1

The H spectrum was broad owing to exorendo iso-

Ž

Ž .

Ž

.

768 9

110 9

y1165 14

y1097 42

y401 8

w x

merisation, but showed resonances characteristic 8 of a

Ž

Ž .

Ž

.

y257 10

h⁴-coordinated cis-1,3-diene. When 1 was added at

room temperature to a vigorously stirred two-phase

system of dichloromethane and aqueous sodium bicar-

Ž

.

Ž

.

y726 14

X

Ž

.

Ž

3524 34

y767 36

Ž

.

bonate pH 8.5 , the green colour was discharged and

the organic layer became deep yellow. Workup of the

dichloromethane layer by column chromatography on

5

Ž

.

Ž

.

4

Ž

. Ž

.x

alumina afforded an excellent yield 81% of the re-

quired complex Mo h -exo-anti-CH ₂CHCH-

CHO CO h -C₅Me₅2, which showed the ex-

2

3

w

Ä

Ž

.

pected IR and NMR spectra see Section 3 . Thus, this

w x

was a major improvement on our earlier work 6 when

this complex was obtained in only 8% yield. The same

approach was also successful for the synthesis of the

corresponding h-cyclopentadienyl complex 4, which

was obtained in 87% yield on hydrolysis in the bi-phasic

4

w

Ä

Ž

.

4

Ž

. Ž

system of Mo h -s-cis-CH₂CHCHCH OAc CO h-

.

xw

x

w

Ž

. Ž .²Ž

C₅H₅BF 3 prepared from Mo NCMe CO h-

C₅H₅BF₄and CH₂5CHCH5CHOAc. The h -inde-

nyl complex 5 was also obtained in moderate yield

2

5

.

xw ⁴x

Ž

.

w x

49% by a variation 9 of this procedure involving low

Ž

.

temperature y508C addition of HBF PEt₂O to a solu-

⁴x

3

5

w

Ž

.Ž . Ž

.

tion of Mo h -C₃H₅CO h -C₉H₇in CH₂Cl₂fol-

2

lowed by addition of 1-acetoxybuta-1,3-diene and then

treatment with aqueous NaHCO₃.

To establish the nature of the bonding and stereo-

chemistry of the related complexes 2, 4, and 5, a single

crystal X-ray diffraction study was conducted with a

suitable crystal of 2. The resulting molecular structure is

illustrated in Fig. 1. Fractional atomic coordinates are

given in Table 1, while selected bond lengths and

interbond angles are listed in Table 2. The anti-oxyallyl

w

ligand, which adopts a partially rotated torsion angle

3

Ž .

x

C14–C15–C16–O3–176 1 8 anti-h -sickle conforma-

5

Ž

. Ž

tion, is bound via C13, C14 and C15 to a Mo CO h -

C₅Me₅fragment, with O3 of the aldehydic carbonyl

Fig. 1. The molecular structure of 2 showing the numbering scheme

used in the text and tables.

2

.

(

)

270

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

1

Table 2

6. An examination of H NMR data showed the pres-

˚

Ž .

Selected bond lengths A and angles 8 for 2

ence of a single set of well-resolved resonances, readily

assignable 11,12 to the exo–anti isomer. Comparison

of the H NMR data with that of similar complexes and

consideration of the magnitude of the J H H cou-

Ž .

Ž

.

Ž .

1.93 2

Mo 1 –C 11

w

x

1

Ž .

Ž

Ž .

1.99 2

Mo 1 –C 12

Ž .

Ž

Ž .

2.328 9

Mo 1 –C 13

b

f

Ž

.

Ž .

Ž

Ž .

2.198 8

Mo 1 –C 14

Ž

.

pling constant 11.0 Hz suggested that the hydroxyl

group was orientated away from the molybdenum cen-

tre, as shown in Scheme 4. Presumably, this trans metal

Ž .

Ž

Ž .

2.332 9

Mo 1 –C 15

Ž . Ž .

Ž .

2.322 7

Mo 1 –C 3

Ž .

Ž

.

Ž .

1.24 2

O 3 –C 16

Ž

.

Ž

.

Ž .

.

Ž .

1.41 2

hydroxyl relationship arises from initial attack by BH^y₄

C 13 –C 14

Ž

.

Ž

Ž .

1.42 2

C 14 –C 15

3

Ž

.

on the exo-face of the rigid h -anti-CH₂CHCH CHO

ligand, followed by a rapid rotation about a C–C bond

to give the less sterically congested product 6.

Ž

.

Ž

Ž .

1.49 2

C 15 –C 16

Ž

.

Ž

.

Ž .

78.9 6

Ž .

124.5 9

122.0 11

Ž

125.0 14

C 11 –Mo 1 –C 12

Ž

.

Ž

.

C 13 –C 14 –C 15

Ž

.

Ž

.

Ž

.

C 14 –C 15 –C 16

Using MeOH as solvent, the reaction with NaBH₄

Ž .

Ž

.

Ž

.

O 3 –C 16 –C 15

Ž

.

was rapid 0.5 h , however, prolonged stirring of the

reaction mixture gave rise to the serendipitous discovery

of an interesting side-reaction. When the reaction of 4

with NaBH₄in MeOH was monitored by TLC, it was

evident that within 0.5 h, complete conversion to 6 had

occurred; however, on stirring for a further 2 h, contin-

ued TLC monitoring showed the gradual formation of

an additional product. When the reaction was continued

for a total of 30 h, TLC analysis of the resulting mixture

revealed the complete consumption of 6, with the new

product being the only detectable species. Following

aqueous work-up and column chromatography, this

product was isolated as a hexane-soluble, yellow crys-

talline solid in 69% yield.

group bent away from the metal centre at a non-bonding

3

˚

distance of 3.979 A. The h -allyl backbone adopts an

exo orientation with respect to the h⁵-C₅Me₅ligand,

Ž .

the C13–C14–C15 bond angle of 124.5 9 8 being typi-

3

w

x

cal 10 of acyclic h -allyl complexes. As with the

3

Ž .

majority of Mo II exo-h -allyls, the inner carbon atom

w

of the allyl moiety is closer to the metal Mo–C14,

˚

Ž .

x

w

2.198 8 A than both the outer carbons Mo–C13,

˚

x

Ž .

2.328 9 and Mo–C15 2.332 9 A . It is interesting to

Ž .

consider the carbon–carbon distances C13–C14 1.41 2

˚

Ž .

and C14–C15 1.42 2 A along with the bond distances

From an examination of the NMR spectra, it was

˚

Ž .

C16–O3 1.24 2 and C15–C16 1.49 2 A, which alto-

gether imply a contribution from the canonical form B

shown in Fig. 2. Such a contribution is also consistent

evident that an h¹-butenyl complex, adopting an exo–

1

anti configuration, had been formed. The H spectrum

of this compound displayed almost identical resonances

to those in the corresponding spectrum of the hydrox-

yallyl complex 6 minus the broad signal of the OH

group , along with a strong singlet at 3.21 ppm, charac-

teristic of a methoxy-substituent. A resonance at 57.2

ppm in the C- H spectrum similarly implied the

presence of a methoxy functionality. On the basis of

w

Ž

.

with the observation of a low-frequency n CO 1644

cm^y1aldehydic carbonyl band in the IR spectrum of 2.

x

Ž

This, of course, suggests that there is a relatively high

barrier to rotation about C15–C16.

.

Having established an efficient procedure for prepar-

ing 4-oxo-h³-butenyl complexes exclusively in the anti

configuration, attention was next turned to a study of

the reactivity of the aldehydic functionality. Addition of

NaBH₄to a methanolic solution of the h-cyclopenta-

13

Ä¹

4

Ž

dienyl substituted complex 4 present as a mixture of

.

Ž

.

exo- and endo-isomers resulted in a fast 0.5 h reac-

tion, and following chromatographic work-up, a yellow

crystalline solid was isolated in 65% yield. Spectro-

scopic and analytical data supported the formation of

the expected hydroxy-substituted h³-allyl complex

3

w

Ä

Ž

.

4

Ž

. Ž

.

x

Mo h -exo-anti-CH₂CHCHCH₂OH CO h-C₅H₅

2

Ž .

Fig. 2.

Scheme 4. i NaBH₄, MeOH, 0.5 h.

(

)

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

271

Table 3

4

Ž

.

Atomic coordinates 1=10 for 7

Atom

Ž .

x

y

z

Ž .

176 1

Ž .

1296 1

Mo 1

Ž .

2140 1

3115 4

619 5

5692 5

Ž .

y1063 5

Ž .

y97 2

O 1

Ž .

368 2

O 2

3286 5

Ž .

1410 2

O 3

Ž .

4719 5

Ž .

Scheme 5. i NaBH₄, MeOH, 30 h.

Ž .

1731 4

C 1

y320 8

y124 7

Ž .

844 8

Ž .

y424 9

Ž .

2263 3

C 2

Ž .

Ž

.

Ž .

2132 3

C 3

1730 6

962 6

y259 5

Ž .

2779 5

1202 5

Ž .

4933 6

4371 5

Ž .

3658 5

4362 5

y1918 10

Ž .

y2540 6

Ž .

1455 3

C 4

Ž .

this evidence, the structure of the product was tenta-

Ž .

1262 3

3

C 5

y1346 7

w

Ä

7

tively identified as Mo h -exo-anti-CH₂CHCHCH₂-

Ž .

y553 7

Ž .

426 2

C 6

5

Ž

.

4

Ž

. Ž

.

x

Ž

.

OMe CO h -C₅H₅

see Scheme 5 and this

2

Ž .

715 2

C 7

2161 6

formulation was supported by elemental analysis and a

Ž .

1513 3

C 8

Ž .

C 10

y157 6

1135 7

2715 6

3678 6

Ž .

5553 9

Ž

.

Ž .

1944 2

FAB mass spectrum FAB MS . The molecular struc-

ture was confirmed by a single crystal X-ray diffraction

study. The molecular structure is shown in Fig. 3.

Fractional atomic coordinates are presented in Table 3,

while selected bond lengths and angles are listed in

Table 4. The molecule shows bond parameters typical

C 9

Ž

.

Ž .

1653 2

Ž

Ž .

1107 2

C 11

Ž

Ž .

906 3

C 12

6490 7

3

5

w

x

w

Ž

.Ž . Ž

.x

the by-product B₂H₆on the oxygen of the hydroxyl

group to generate a potentially good leaving group, i.e.,

10 of a Mo h -allylic CO h -C₅H₅complex,

2

themethoxy-substituent being orientated away from the

metal, i.e., trans to Mo as implied by a J H H

HOBH^y₃. As illustrated, fragmentation then affords the

b

f

Ž

.

4

w

Ä

buta-1,3-diene substituted cation Mo h -exo-1,3-

coupling of 11.2 Hz.

4

Ž

. Ž

.

xw

x

C₄H₆CO h-C₅H₅HOBH₃, which is captured by

It is suggested that the formation of 7 involves the

steps depicted in Scheme 6. Delivery of hydride anion

by BH^y₄to the aldehydic carbonyl group forms the

hydroxy-substituted complex 6, which then reacts with

2

reaction with methanol to form the isolated product 7.

Support for this mechanism came from a study of the

corresponding reaction of 4 with NaBD₄in MeOH over

30 h. Standard chromatographic work-up led to the

isolation of a hexane-soluble solid in 60% yield, and

examination of the spectroscopic data revealed that the

product was a 1:1 mixture of the deuterio-isomers shown

in Scheme 7. As required by the mechanism shown in

Scheme 6, ‘D^y’ is delivered to the CHO carbon atom

to form an alcohol, which, on coordination of ‘BD₃’

and dissociative loss of HOBD^y₃, forms the cation

Mo h -exo-CH D 5CHCH5CH₂CO h-C₅H₅

4

w

Ä

Ž .

4

Ž

. Ž

.

x^q

.

2

This cation then reacts with OMe supplied by the

methanol at either end of the coordinated buta-1,3-diene

to form the two isomers shown in Scheme 7.

Table 4

˚

Ž .

Selected bond lengths A and angles 8 for 7

Ž . Ž .

Mo 1 –C 7

Ž .

1.942 5

Mo 1 –C 6

Ž . Ž .

Ž .

1.970 5

Ž . Ž .

Ž .

2.217 4

Mo 1 –C 9

Ž . Ž .

Ž .

2.320 5

Mo 1 –C 8

Ž .

O 3 –C 12

Ž

.

Ž .

2.340 4

Mo 1 –C 10

Ž .

Ž

.

Ž .

1.417 6

Ž .

O 3 –C 11

1.417 5

Ž .

1.412 7

Ž . Ž .

C 8 –C 9

Ž .

Ž

.

Ž .

1.411 7

C 9 –C 10

Ž

.

Ž

.

Ž .

1.484 5

C 10 –C 11

Ž . Ž . Ž .

Ž .

80.8 2

C 6 –Mo 1 –C 7

Ž

.

Ž .

Ž . Ž .

Ž

.

Ž .

111.6 4

C 12 –O 3 –C 11

C 10 –C 9 –C 8

Ž .

119.4 4

Ž .

Ž

.

Ž

Ž .

121.1 4

C 9 –C 10 –C 11

Fig. 3. The molecular structure of 7 showing the numbering scheme

used in the text and tables.

Ž .

.

Ž .

109.4 3

O 3 –C 11 –C 10

(

)

272

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

5

w

x

Ž

. Ž

. Ž .

Ž .

Scheme 6. M sMo CO h -C₅H₅. i NaBH₄rMeOH, 30 h; ii

2

Ž

.

Ž .

qB₂H₆; iii yHOBH₃; iv qOMe.

The h⁵-C₅Me₅substituted exo–anti aldehyde com-

plex 2 showed a similar reactivity towards NaBH₄.

Treatment of a methanolic solution of 2 with NaBH₄

followed by stirring at ambient temperature for 1 h,

resulted in the formation of the corresponding exo–anti

hydroxy complex 8, isolated as yellow crystals in 62%

yield. The NMR spectral data for 8 was similar to the

analogous h⁵-C₅H₅complex, implying an identical ori-

entation of the h³-hydroxy allyl ligand. As before, an

extended reaction time led to the formation of a

methoxy-substituted compound 9 with the analogous

spectral features, to 7.

Ž .

Ž . Ž .

NaBH₄, thf, 0.5 h; ii HBF₄PEt₂OPCH₂Cl₂; iii

Scheme 8.

w

i

n

x

Ž

. w

xw

x

Na BH₃CN , thf; iv Bu₄N RuO₄, morpholine-N-oxide, CH₂Cl₂.

agreement with there being a contribution from the

Ž

.

Ž

.

canonical form B Fig. 2 , protonation y788C of a

solution of 2 in dichloromethane with HBF₄PEt₂O af-

Ž

.

forded 90% yield the orange crystalline complex

Mo h -exo-syn-s-cis-CH₂CHCHCH OH CO h -

C₅Me₅BF₄10, Scheme 8 characterised by elemen-

tal analysis, IR and NMR spectroscopy see Section 3 .

4

5

w

Ä

Ž

.

4

Ž

. Ž

2

.

xw

x

Ž

.

Ž

.

w

x

Ž

.

When Na BH₃CN was added 08C to a suspension of

10 in thf, a rapid reaction occurred resulting in the

An alternative synthesis of the alcohol 8 was also

explored, which relates to our earlier finding that O-pro-

Ž

.

formation of the alcohol 8 in excellent yield 85% .

Thus, as illustrated in Scheme 8, selective nucleophilic

attack by ‘H^y’ occurs on the hydroxy-substituted car-

bon atom of the coordinated 1,3-diene, an observation

Ž

.

tonation HBF₄of the syn-aldehyde substituted com-

4

w

Ä

Ž

.4

plexes Mo h -exorendo-syn-CH ₂CHCH CHO -

5

Ž

. Ž

.x

CO h -C₅Me₅affords via an overall rotation

2

about the C²rC³axis of the allyl ligand, the

w

x

4

that is in accord with our earlier studies 13 and those

w

Ä

hydroxy-substituted 1.3-diene cation Mo h -exo-s-

w

x

w x

5

x^q

of Hansson et al. 14 and Rubio and Liebeskind 15 .

Initial attempts to reverse the reduction reaction by

Ž

.

4

Ž

. Ž .

cis-CH₂CHCHCH OH CO h -C₅Me₅10. Al-

though, as is summarised in Scheme 1, this cation is

2

Ž

.

oxidation Swern were unsuccessful. However, it was

deprotonated by triethylamine to form the anti-aldehyde

2

w

x

found that a catalytic amount of the Ley–Griffiths 16

w x

substituted complex 2 6 , we reasoned that it might be

n

w

xw

x

reagent Bu₄N RuO₄in the presence of morpholine-

N-oxide at room temperature converted the alcohol 6

into 4 in 60% yield, and a similar reaction with 8

afforded 2 in comparable yield see Scheme 8 . This is

an interesting result showing that the ruthenium reagent

can be used to selectively oxidise an alcohol functional-

ity without destroying a relatively sensitive metal com-

plex.

possible to use a relatively non-basic borohydride to

selectively deliver ‘H^y’ to the hydroxy-substituted car-

bon of the 1,3-diene. This idea proved to be correct. In

Ž

.

Returning to the study of nucleophilic attack on the

aldehyde carbonyl carbon atom, methylmagnesium io-

Ž

.

dide was added y208C to a solution of 4 in thf which

3

Ž

.

w

Ä

resulted, on workup, in the formation 70% of Mo h -

exo-anti-CH₂CHCHCH OH Me CO h -C₅H₅11.

Similarly, reactions between 4 and EtMgBr or PhMgCl

5

Ž

.

4

Ž

. Ž .x

2

Ž

.

Ž

.

afforded 12 53% and 13 57% respectively, and

2

Ž .

Scheme 7. i NaBD₄PMeOH, 30 h.

w x

See also Ref. 17 .

(

)

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

273

Table 5

Ž

.

reaction of 6 with MeLi gave 14 75% . All of these

diastereomeric complexes, i.e., chiral at the carbon and

molybdenum centres, were fully characterised by ele-

mental analysis, IR and NMR spectroscopy.

4

Ž

.

Atomic coordinates 1=10 for 15

Atom

x

y

z

Ž .

2231 1

Ž .

2081 1

2284 3

4969 3

2192 4

3884 5

3226 5

3457 5

2005 5

Ž .

2319 1

Mo 1

Ž .

3616 2

O 1

y121 4

It was clearly interesting to also explore the possibil-

ity of oxidation of these alcohols into ketone substituted

h³-allyl complexes that would have potential for enolate

chemistry. However, an attempt to carry out an Oppe-

nauer oxidation of the alcohol Mo h -exo-anti-

Ž .

3346 3

Ž .

3512 2

O 2

Ž .

3142 3

C 1

778 5

2962 4

2510 5

991 5

294 5

1345 5

2723 5

2419 4

3732 4

4692 4

5041 5

6323 5

Ž .

3080 3

C 2

Ž .

911 3

C 3

3

w

Ä

Ž .

1036 3

C 4

5

Ž .

983 3

C 5

Ž

.

4

Ž

. Ž

.x

CH₂CHCHCH OH Me CO h H₅H₅11 was un-

successful. When a solution of 11 and Al OPr

2

Ž .

838 3

i

C 6

886 5

Ž

.

3

in

Ž .

783 3

C 7

1643 5

y224 4

acetone and toluene was heated under reflux, a single

product, 15, was formed. Following chromatographic

work-up, a hexane-soluble yellow solid was isolated in

47% yield. From an initial examination of the spectro-

scopic and analytical data, it was evident that the ex-

pected MeCO-substituted h³-allylic complex had not

Ž .

3168 3

C 8

Ž .

C 10

Ž .

2804 3

C 9

Ž

84 4

.

Ž .

3151 3

1336 4

1783 5

2461 5

Ž

Ž .

4131 3

C 11

Ž

Ž .

4548 3

C 12

1

been formed. The H NMR spectrum showed exo-h³-

b

c

Ž

.

Ž

.

allyl proton resonances at d4.50 H , 4.19 H , 2.84

structural identity of 15, a single crystal X-ray diffrac-

tion study was carried out. Fig. 4 shows the geometry of

the molecule and the atomic numbering scheme used.

Fractional atomic coordinates are given in Table 5,

while selected bond lengths and angles are listed in

Table 6.

d

e

Ž

.

Ž .

H

and 1.47 H , along with three proton resonances

attributable to an uncoordinated vinyl group, suggesting

that 15 was surprisingly an h³-pentadienyl complex. In

w

x

fact, we had previously 6,7 synthesised an analogous

h⁵-C₅Me₅substituted complex Mo h -exo-anti-

3

w

Ä

5

Ž

.

4

Ž

. Ž

.x

CH₂CHCH CH5CH₂CO h -C₅Me₅by reaction

As surmised, the molecule contains a pentadienyl

2

fragment in a anti-h³-sickle conformation in which C8,

of 2 with the Wittig reagent Ph₃P5CH₂, or by deproto-

nation 18 NEt₃of the h⁴-penta-1,3-diene cationic

5

w

x

Ž

.

w

Ž

. Ž

.x

C9 and C10 are bound to a Mo CO h -C₅H₅frag-

ment with C11 bent away from the metal. As in the case

of the related aldehyde-substituted system 2, where the

2

3

w

2

Ä

co m plex

M o h -exo-syn -C H ₂5 C H C H 5

5

Ž

.

4

Ž

. Ž

.

xw

x

CH Me CO h -C₅Me₅BF₄, and comparison of

1

the H NMR data for 15 with that for the h⁵-C₅Me₅

plane of the CHO group is rotated relative to the

3

w

system showed a close correspondence. To confirm the

h -allyl plane, the vinyl group is partially rotated tor-

Ž

.x

sion angle C9–C10–C11–C12: 151.0 0.4 . Interest-

ingly, it has recently 19 been reported that the sequen-

w

x

1

w

Ä

Ž

.

tial reaction of

W h -C H C [ C C M e 5

2

5

4

Ž

. Ž

.

x

CH₂CO h -C₅H₅

with CF₃SO₃H and MeOH

3

w

Ä

affords an h -pentadienyl complex W h -endo-anti-

3

5

Ž

.

Ž

.

4

Ž

. Ž .x

h -CH₂C CO₂Me CH CMe5CH₂CO h -C₅H₅,

2

but in contrast with 15, an X-ray structure of the

tungsten species established that it adopts an anti-h³-U

conformation.

Table 6

˚

Ž .

Bond lengths A and angles 8 for 15

Ž . Ž .

Mo 1 –C 1

Mo 1 –C 2

Ž .

1.938 4

Ž . Ž .

Ž .

1.957 4

Ž . Ž .

Ž .

2.343 5

Mo 1 _C 5

Ž . Ž .

Ž .

2.343 4

Mo 1 –C 8

Ž . Ž .

Ž .

2.230 4

Mo 1 –C 9

Ž .

Ž

.

Ž .

Mo 1 –C 10

2.397 4

Ž .

1.411 6

Ž . Ž .

C 8 –C 9

C 9 –C 10

Ž .

Ž

.

Ž .

1.421 6

Ž

.

Ž

.

Ž .

1.449 6

C 10 –C 11

Ž

Ž .

1.331 7

C 11 –C 12

Ž . Ž . Ž .

Ž .

78.8 2

C 1 –Mo 1 –C 2

Ž . Ž .

Ž

.

Ž .

120.5 4

C 8 –C 9 –C 10

Ž .

Ž

.

Ž

.

Ž .

123.7 4

C 9 –C 10 –C 11

Fig. 4. The molecular structure of 15 showing the numbering scheme

used in the text and tables.

Ž

.

Ž

.

Ž

.

Ž .

124.6 4

C 12 –C 11 –C 10

(

)

274

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

The failure to convert 11 into 4 was disappointing;

however, preliminary experiments indicate that the

Ley–Griffiths ruthenium reagent can also be used to

oxidise the alcohols 11, 12 and 13 to the corresponding

anti-keto-substituted h³-allyl complexes, and we are

presently exploring this chemistry.

The availability of the hydroxy-substituted h³-allyls

6, 8, 11, 12 and 13 presented a further opportunity for

the stereocontrolled functionalisation of allylic systems.

w

x

Specifically, it is known 20,21 that the unsubstituted

3

w

Ž

.Ž . Ž

.x

h -allyl complexes Mo h -allyl CO h-C₅H₅react

2

w

xw

x

with NO BF in acetonitrile to form the cationic

w⁴

Ž

.Ž

.

xw

x

3

complexes Mo h -allyl CO NO h-C₅H₅BF₄,

which react selectively with nucleophilic reagents on

the end carbons of the h³-allyl ligand to form alkene

complexes. Therefore, in principle, it might be possible

to nitrosate the hydroxy-substituted allyl complexes and

then promote a cyclisation reaction by removal of a

proton from the pro-nucleophilic hydroxy centre. Of

course, for such a reaction to be successful, there are

problems of stereoselectivity, and it is interesting to

w x

note that in the study of Liu et al.

5

of the

3

h ³-allylnitroso cation

M o h -exo-syn-anti-

w

Ä

Ž

.

4

Ž

.Ž

.

xw

x

EtCHCHCHCH₂CH OH Ph CO NO h-C₅H₅BF₄,

where the hydroxy group is present in an anti-allylic

side chain, decomplexation occurs and an isoxazole is

formed.

Ž . w xw

x

Ž .

Scheme 9. i NO BF₄, MeCN, 08C; ii Na₂CO₃, MeCN.

Ž

.

w

xw

x

Addition 08C of NO BF₄to an acetonitrile solu-

Ž

.

tion of 11 led to a rapid 0.25 h reaction and the

formation of a nitrosylcarbonyl substituted cation, which

was characterised by the presence in the IR spectrum of

then the exo-cationic species A is formed. Rotation of

y CO and y NO bands at 2072 and 1721 cm^y1

,

the CH Me OH anti-h -allylic group then gives the

exo-cation B, in which the hydroxyl group on deproto-

3

Ž

.

Ž

.

Ž

.

respectively. Addition of an excess of anhydrous

Na₂CO₃to the acetonitrile solution of this cation re-

Ž

.

nation Na₂CO₃is ideally placed for intramolecular

nucleophilic attack on the terminal h³-allylic carbon cis

to the NO ligand, thus leading to the formation of an

exorendo mixture of the neutral fur-3-ene complex 16.

Competing with this sequence of reactions is the re-

versible formation of the endo-cation A, which can

similarly undergo rotation about a C–C bond to give the

endo-cation B, and since it is known that nucleophilic

attack occurs trans to the coordinated NO in the endo-

isomer, this pathway also leads to the same endorexo

isomeric mixture of fur-3-ene complexes 16. We are

presently exploring the potential of this synthetic

methodology.

Ž

.

sulted in the gradual 4 h disappearance of these bands

Ž

.

and their replacement by bands at 1975 CO and 1622

NO cm^y1. Work-up by column chromatography gave

Ž

.

a single yellow band, which on recrystallisation

gave a yellow low melting solid characterised by a

1

FAB MS and by H NMR as an exorendo mixture

2

w

Ä

of the fur-3-ene substituted complexes Mo h -

Ž

.

4

Ž

.Ž

.

x

Ž

60%

H Me CO NO h-C₅H ₅

.Ž

.

yield Scheme 9 .

The diastereoselective formation of 16 is especially

interesting because substituted furanyls are building

blocks in a wide range of compounds of physiological

and pharmacological importance. Particularly interest-

ing is the fact that there is complete control over the

stereochemistry at the methyl-substituted carbon atom 2

of the coordinated fur-3-ene, with the implication that if

the corresponding chemistry was developed with chiral

substituents on the h⁵-C₅H₅ring, then complete enan-

tioselective control could be achieved at this centre. The

3. Experimental

13

The ¹H, C- H NMR spectra were recorded on

JEOL GX270 and EX400 spectrometers. Data are given

for room temperature measurements unless otherwise

stated. Chemical shifts are referenced relative to tetram-

ethylsilane. Infrared spectra were recorded on a Nicolet

580P FT-IR spectrometer. Reactions were carried out in

Ä¹

4

origins of this selectivity are outlined in Scheme 9. In

q

w x

particular, if it is assumed 4 that NO replaces CO

3

Ž

.

trans to the CH OH Me group of the exo-h -allyl 11,

(

)

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

275

Schlenk tubes under atmospheres of dry oxygen-free

nitrogen, using freshly distilled and degassed solvents.

Column chromatography was performed using BDH

alumina, Brockman activity II.

yellowish in colour. After 2 h, the aqueous layer was

removed and extracted several times with CH₂Cl₂. The

extracts and organic layer were combined and washed

with several portions of water before drying over mag-

nesium sulphate. The mixture was filtered, and the

yellow filtrate was concentrated to a small volume

under reduced pressure before being chromatographed

on alumina. Elution with Et₂O afforded a single yellow

fraction which gave, after removal of solvent and re-

crystallisation from Et₂O, bright yellow crystals of 2

3.1. Preparations

4

5

[

)][

{

(

)

}

(

) (

3.1.1. Mo h -syn-s-cis-CH₂CHCHCH OAc CO ₂h -

]

1

C₅Me₅BF₄

Ž

An excess of 1-acetoxybuta-1,3-diene 0.460 ml,

0.435 g, 3.88 mmol was added to a solution of the

blood-red complex cis- Mo NCMe CO h -

Ž

. Ž

1.15 g, 81% Found: C, 54.0; H, 5.7. C₁₆H₂₀MoO₃

.

Ž

.

Ž

.

1

requires C, 53.9; H, 5.7% . IR CH₂Cl₂: y CO 1960

5

vs, 1883 s and 1644 m cm^y1. NMR CD₂Cl₂: H d,

w

Ž

. Ž

Ž

.

2

a

b

c

.

xw

x

Ž

.

Ž

C₅Me₅BF₄0.177 g, 0.388 mmol in CH₂Cl₂25

w

Ž

.

x

w

7.00 d, 1H, H , J H H 7.8 , 3.51 ddd, 1H, H ,

c

e

c

d

c

b

.

ml and the mixture was stirred at room temperature for

Ž

.

Ž

.

Ž

.

x

Ž

J H H 11.6, J H H 8.4, J H H 7.1 , 3.42 m,

1H, H , 2.28 ddd, 1H, H , J H H 8.4, J H H

2.8, J H H 1.4 , 1.88 s, 15H, C₅Me and 1.75 dd,

1H, H , J H H 11.6, J H H 2.8 ; C- H , d

b

d

c

d e

4 days. Monitoring by infrared spectroscopy showed the

gradual consumption of the starting material and the

formation of a new product. The solvent was removed

in vacuo, and the resulting green-brown residue was

extracted with CH₂Cl₂and filtered through Celite. The

bottle-green filtrate was concentrated to a small volume

under reduced pressure, after which, the addition of

Et₂O precipitated a green solid. The supernatant liquid

was removed via syringe and the solid washed with

several portions of Et₂O, then pentane. A further purifi-

cation was effected by recrystallisation from

.

w

Ž

.

Ž

.

d

b

Ž

.

x

Ž

.

w

Ž

.

Ž

.

⁵x

Ä¹

4

13

c

e

c

e

d

1

Ž

.

Ž

.

Ž

.

Ž

.

237.5 CO , 237.2 CO , 184.8 C , 104.9 C₅Me₅,

3

2

4

Ž

.

Ž

.

Ž

80.1 C , 65.0 C , 42.4 C and 10.4 C₅Me₅.

w

x^qx^qx^q

w

FAB MS MH 359, M–CO 330, M–CO 302.

4

5

[

{

(

)

}

(

) (

3.1.3. Mo h -syn-s-cis-CH₂CHCHCH OAc CO ₂h -

)][

]

3

C₅H₅BF₄

3

Ž

An excess of 1-acetoxybuta-1,3-diene 9.40 cm , 79.0

.

mmol was added to a solution of the blood-red com-

Ž

CH₂Cl₂rEt₂O to afford green crystals of 1 0.133 g,

5

w

Ž

. Ž . Ž

.

xw

x Ž

plex cis- Mo NCMe CO h -C₅H₅BF₄3.05 g,

2

. Ž

71% Found: C, 45.0; H, 5.0. C₁₈H₂₃BF₄MoO₄re-

.

Ž

.

7.90 mmol in CH₂Cl₂55 ml . After stirring at ambi-

ent temperature for 2 days, a bright yellow precipitate

was observed. Stirring was continued for a further 2

days, resulting in the formation of more precipitate. The

mixture was filtered via cannula, and the yellow solid

was washed with several portions of CH₂Cl₂, then

pentane. Removal of the solvent in vacuo, afforded

.

Ž

.

Ž

.

quires C, 44.5; H. 4.8% . IR CH₂Cl₂: y CO 2053 vs,

1

2006 s and 1759 mw cm^y1. NMR CD₂Cl₂: H, d

.

c

b

a

Ž

.

Ž

.

w

6.08 m, 1H, H , 5.97 m, 1H, H , 4.58 d, 1H, H ,

a

b

d

e

Ž

.

x

w

Ž

.

x

Ž

J H H 6.8 , 2.57 d, 1H, H , J H H 7.8 , 2.03 s,

c

.

Ž

.

w

3H, Me , 1.98 s 15H, C₅Me₅and 1.05 d, 1H, H ,

13

c

d

Ž

.

x

Ä¹

4

Ž

.

Ž

.

J H H 10.7 ; C- H d 221.6 CO , 220.3 CO ,

169.3 C , 106.1 C₅Me₅, 100.1 C , 95.3 C or

C , 89.0 C or C , 59.5 C , 20.5 Me and 10.8

5

1

2

Ž

.

Ž

.

Ž

. Ž

3

2

3

4

yellow crystals of 3 2.80 g, 85% Found: C, 37.0; H,

3.2. C₁₃H₁₃BF₄MoO₄requires C, 37.5; H, 3.1% . IR

.

Ž

.

Ž

.

Ž

.

C₅Me₅.

Ž

.

Ž

.

CH₃NO₂: y CO 2068 vs, 2020 s and 1759 mw

1

cm^y1. NMR d -acetone : H, d 6.48 br m, 1H, H ,

6

b

Ž

.

Ž

.

c

Ž

.

Ž

.

w

6.29 br m, 1H, H , 6.12 s, 5H, C₅H₅, 6.07 br d,

a

b

d

c

Ž

.

x

w

Ž

.

1H, H , J H H 6.8 , 3.01 ddd, 1H, H , J H H

c

d

e

d

b

Ž

.

Ž

.

x

w

7.8, J H H 2.0, J H H 1.4 , 2.38 br d, 1H, H ,

13

c

Ž

.

x

Ž

.

Ä¹

4

1

J H H 10.7 and 2.06 s, 3 H, Me ; C- H , d 220.2

5

2

Ž

.

Ž

.

Ž

.

Ž

.

Ž

CO , 219.2 CO , 167.9 C , 102.8 C , 93.9 C or

3

2

3

4

.

Ž

.

Ž

.

C , 91.6 C₅H₅, 88.3 C or C , 50.0 C , 20.5

Ž

.

Me .

3

[

{

(

)

}

(

) (

)]

3.1.4. Mo h -anti-CH₂CHCH CHO CO ₂h-C₅H₅

4

3

5

[

)]

{

(

)

}

(

) (

Ž

3.1.2. Mo h -exo-anti-CH₂CHCH CHO CO h -

Sodium hydrogen carbonate 75 ml of a 0.1 M

2

.

C₅Me₅

2

aqueous solution, pH 8.5, ca. 7.50 mmol was added to

a solution of the yellow complex 3 3.00 g. 7.21 mmol

in CH₂Cl₂60 ml . The two-phase system was vigor-

ously stirred at room temperature for 0.5 h. The aqueous

layer was removed and extracted several times with

CH₂Cl₂. The extracts and organic layer were combined

Ž

.

Sodium hydrogen carbonate 50 ml, of a 0.1 M

aqueous solution, pH 8.5, ca. 5.0 mmol was added to a

.

Ž

.

Ž

.

solution of the green complex 1 1.94 g, 3.99 mmol in

Ž

.

CH₂Cl₂50 ml . The two-phase system was vigorously

stirred at room temperature, causing the mixture to turn

(

)

276

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

Ž

and washed with several portions of water, before dry-

ing over magnesium sulphate. The mixture was filtered,

and the yellow filtrate was concentrated to a small

volume under reduced pressure, before being chromato-

graphed on alumina. Elution with CH₂Cl₂afforded a

bright yellow band which gave, after removal of solvent

and recrystallisation from CH₂Cl₂rhexane, bright yel-

was treated with 1-acetoxybuta-1,3-diene 2.73 ml, 22.98

.

mmol and allowed to warm to ambient temperature,

producing a green-black viscous mixture. This was

stirred for a further 1 h and then filtered through Celite

to give a dark green solution. The filtrate was concen-

trated to a dark residue in vacuo, redissolved in CH₂Cl₂

80 ml and treated with sodium hydrogen carbonate

135 ml of an aqueous solution, pH 8.5, ca. 13.79

mmol . The two-phase system was vigorously stirred at

room temperature for 0.5 h, causing the mixture to turn

dark yellow in colour. The aqueous layer was removed

and extracted several times with CH₂Cl₂. The extracts

and organic layer were combined and washed with

several portions of water before drying over magnesium

sulphate. The mixture was filtered through a pad of

alumina, and the orange-yellow filtrate was concen-

trated to a small volume under reduced pressure before

being chromatographed on alumina. Elution with

CH₂Cl₂afforded a bright yellow fraction which gave,

after removal of solvent and recrystallisation from

Ž

.

Ž

. Ž

low crystals of 4 1.80 g, 87% Found: C, 46.3; H, 3.5.

.

Ž

.

C₁₁H₁₀MoO₃requires C, 46.2; H, 3.5% . IR CH₂Cl₂:

n CO 1973 vs, 1896 s and 1649 m cm^y1. NMR

Ž

.

1

a

Ž

.

Ž

.

CD₂Cl₂exo–anti: isomer H, d 7.14 br s, 1H, H ,

c

Ž

.

Ž

.

Ž

5.40 br s, 5H, C₅H₅, 4.76 br s, 1H, H , 4.05 br s,

b

d

e

.

Ž

.

x

1H, H , 3.03 br s, 1H, H and 1.77 br s, 1H, H ;

a

b

Ž

.

w

Ž

.

CD₂Cl₂, y408C : d 6.98 d, 1H, H , J H H 7.9 ,

c

e

Ž

.

w

Ž

.

5.40 s, 5H, C₅H₅, 4.78 ddd, 1H, H , J H H 11.9,

c

d

a

c

b

Ž

.

Ž

. x

w

J H H

8.2, J H H

7.0 , 4.00 ddd, 1H, H ,

b

c

b

d

Ž

.

Ž

.

x

b

w

J H H 7.9, J H H 7.0, J H H 1.4 , 3.02 ddd,

d

c

d

e

d

Ž

.

Ž

.

Ž

.

1H, H . J H H 8.2, J H H 2.7, J H H 1.4 and

1.68 dd, 1H, H , J H H 11.9, J H H 2.7 . ¹³C-

e

c

d

w

Ž

.

Ž

.

x

Ä¹

4

Ž

.

Ž

.

Ž

H , d 234.7 br s, CO , 234.3 br s, CO , 186.7 br s,

C , 92.2 br s, C₅H₅, 72.2 br s, C , 59.5 br s, C

1

3

2

.

Ž

.

Ž

.

Ž

.

Ž

CH₂Cl₂rhexane, bright yellow crystals of 5 1.51 g,

Ž

⁴. Ž

Ž

3

.

. Ž

and 40.2 br s, C ; CD₂Cl₂, y508C : d 234.7 CO ,

49% Found: C, 53.5; H, 3.6. C₁₅H₁₂MoO₃requires C,

1

Ž

.

Ž

4

.

Ž

.

Ž

.

Ž

.

234.5 CO , 186.1 C , 92.0 C₅H₅, 71.8 C 58.7

53.6; H, 3.6% . IR CH₂CL₂: y CO 1973 vs, 1896 s

1

2

and 1649 m cm^y1. NMR CD₂Cl₂: H y208C , d

Ž

.

Ž .

and 40.0 C .

Ž

.

Ž

.

C

a

a b

Ž

.

w

Ž

.

7.25–7.08 m, 4H, indenyl , 6.86 d, 1H, H , J H H

x

Ž

.

Ž

.

a

8.2 , 6.18 m, 1H, indenyl , 6.06 m, 1H, indenyl , 5.60

m, 1H, indenyl , 3.35 ddd, 1H, H , J H H 8.2,

1.3 . 2.52 ddd, 1H, H ,

J H H 8.7, J H H 2.2, J H H 1.3 , 1.83 dd,

b

Ž

.

w

Ž

.

b

c

b

d

Ž

.

Ž

. x

w

J H H

7.4, J H H

d

c

d

b

Ž

.

Ž

.

Ž

d

.

x

w

c

e

c

Ž

.

x

w

1H, H , J H H 12.2 J H H 2.2 and 0.40 ddd, 1H,

H , J H H 12.2, J H H 8.7, J H H 7.4 ; ¹³C-

c

e

c

d

c

b

Ž

.

Ž

.

Ž

.

x

1

Ä¹

4

Ž

.

Ž

.

H , d 235.2 CO , 234.1 CO , 185.6 C , 126.5,

Ž

.

Ž

.

126.4 indenyl , 124.4, 124.0 indenyl , 112.6, 112.3

1

a

3

Ž

.

Endo–anti isomer H, d 7.84 br s, 1H, H , 5.30

Ž

.

Ž

.

Ž

.

indenyl , 89.5 indenyl , 87.9 C . 81.0, 80.2 indenyl ,

69.2 C and 48.2 C . FAB MS, MH 339, M–

c

2

4

Ž

.

Ž

.

w

x^q

w

Ž

.

Ž

.

Ž

br s, 5H, C₅H₅, 4.50 br s, 1H, H , 4.19 br s, 1H,

H , 2.78 br s 1H, H and 2.65 br s, 1H, H ;

b

d

e

x^q

w

x^q

.

Ž

.

Ž

.

CO 310, M–2CO 282.

a

b

Ž

.

w

Ž

.

b

x

CD₂Cl₂, y408C : d 7.71 d, 1H, H , J H H 7.9 ,

c

e

Ž

.

w

Ž

5.30 s, 5H, C₅H₅_c, 4.46 ddd, 1H, H , J H H 11.2,

c

d

b

a

3

5

Ž

.

Ž

.

x

w

Ž

.

J H H 7.3, J H H 6.2 , 4.28 dd, 1H, H , J H H

[

{

(

)

}

(

) (

3.1.6. Mo h -exo-anti-CH₂CHCHCH₂OH CO ₂h -

b

c

d

c

Ž

.

x

w

c

Ž

.

x

7.9, J H H 6.2 , 2.77 d, 1H, H , J H H 7.3 and

2.65 d, 1H, H , J H H 11.2 ; C– H , d 234.7 br

)]

C₅H₅

6

13

e

w

Ž

.

x

Ä¹

4

Ž

.

Sodium borohydride 0.02 g, 0.529 mmol was added

to a solution of 4 0.10 g, 0.349 mmol in methanol 10

ml , and the mixture was stirred at ambient temperature

for 0.5 h. Monitoring by infrared spectroscopy indicated

the complete consumption of starting material and the

formation of a new product. Water 0.5 ml was added,

and the mixture was stirred for 0.5 h before the solvents

were removed in vacuo. The yellow residue was ex-

tracted with several portions of Et₂O, which were con-

centrated to a small volume under reduced pressure and

chromatographed on alumina. Elution with

1

.

Ž

.

Ž

.

Ž

s, CO , 234.3 br s, CO , 186.7 br, s, C , 92.2 br s,

Ž

.

Ž

3

2

Ž

.

Ž

.

Ž

C₅H₅, 72.2 br s, C , 59.5 br s, C and 40.2 br s,

.

4

.

Ž

.

Ž

.

Ž

.

C ; CD₂Cl₂y508C : d 235.4 CO , 235.1 CO ,

1

3

2

Ž

.

Ž

.

Ž

.

Ž

.

186.6 C , 90.9 C₅H₅, 86.4 C , 61.0 C and 34.2

4

Ž

.

w x^q

w

x^q

w

x^q

C . FAB MS M 288, M–CO 260, M–2CO

Ž

.

232.

3

5

[

5

{

(

)

}

(

) (

2

3.1.5. Mo h -exo-anti-CH₂CHCH CHO CO h -

C₉H₇

)]

3

w Ž

solution of the yellow complex Mo h -

A

5

.Ž . Ž

.

x

Ž

.

Ž

.

C₃H₅CO h -C₉H₇2.83 g, 9.19 mmol in CH₂Cl₂

Et₂Orhexane 1:1 afforded a yellow fraction which

2

Ž

50 ml was cooled to y508C. To this was added

gave, after removal of solvents and recrystallisation

Ž

HBF₄POEt₂1.74 ml, 2.01 g of an 85% Et₂O solution,

from CH₂Cl₂rpentane, yellow crystals of 6 0.065 g,

.

.Ž

10.57 mmol resulting in an immediate colour change to

65% Found:C, 46.0; H, 4.2, C₁₁H₁₂MoO₃requires C,

.

Ž

.

Ž

.

dark red. After stirring for 0.5 h at y508C, the mixture

45.9; H, 4.2% . IR CH₂Cl₂: y CO 1948 s and 1865 s

(

)

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

277

1

cm^y1. NMR CDCl₃: H, d 5.28 s, 5H, C₅H₅, 4.12

3

Ž

.

Ž

.

c

[

{

(

)}

3.2. Reaction of Mo h -anti-CH₂CHCH CHO -

c

e

c

b

d

5

w

Ž

.

Ž

.

Ž

.

(

) (

)]

ddd, 1H, H , J H H 11.4, J H H 7.7, J H H

CO ₂h -C₅H₅4 with NaBD₄

b

a

x

Ž

.

Ž

.

w

7.5 , 3.93 m, 1H, H , 3.78 m, 1H, H , 2.94 ddd, 1H,

H , J H H 7.5, J H H 2.4, J H H 1.6 , 2.14

d

c

d

e

d

b

Ž

An excess of sodium borodeuteride 0.012 g, 0.287

mmol was added to a solution of the yellow complex 4

0.06 g, 0.210 mmol in methanol 7 ml and the

Ž

.

Ž

.

Ž

.

x

f

b

.

w

Ž

.

x

Ž

.

dd, 1H, H , J H H 11.0 , 1.50 br s, 1H, OH and

1.41 dd, 1H, H , J H H 11.4, J H H 2.4 ; ¹³C-

e

c

e

d

Ž

.

Ž

.

w

Ž

.

Ž

.

x

Ä¹

4

Ž

.

Ž

.

Ž

.

Ž

.

mixture was stirred for 30 h. Water 0.5 ml was added

and the mixture was stirred for 0.5 h, after which the

solvents were removed in vacuo. The yellow residue

was extracted with several portions of Et₂O, which

were concentrated to an oil under reduced pressure and

redissolved in a small volume of hexane, before being

chromatographed on alumina. Elution with hexane af-

forded a single yellow fraction which gave, after re-

H , d 236.8 CO , 236.3 CO , 91.6 C₅H₅, 69.1

C . 66.6 C , 53.9 C and 38.1 C . FAB MS,

1

3

2

4

Ž

.

Ž

.

Ž

.

Ž

w

x^q

w

x^y

w

x^q

M–OH

217.

273, M–OH–CO

245, M–OH–2CO

moval of solvent and recrystallisation from hexane

3

Ž

.

w

Ž

y308C , a 1:1 isomeric mixture of Mo h -exo-

5

Ž

.

4

Ž

. Ž

.

x

anti-CH ₂CHCHCH OMe D CO h -C₅H ₅

7a

²Ž

.

4

Ž

. Ž

3

5

w

Ž

and Mo h -exo-anti-CHDCHCHCH₂OMe CO h -

2

.

x

Ž

.

C₅H₅7b obtained as a yellow solid 0.038 g, 60% .

Found: C, 46.9; H, 4.6, C₁₂H₁₃DMoO₃requires C,

Ž

3

.

Ž

.

Ž

.

[

{

(

)

}

(

)

47.5; H, 4.3% . IR CH₂Cl₂; y CO 1948 vs and 1865

3.1.7. Mo h -exo-anti-CH₂CHCHCH₂OMe CO -

2

1

s cm^y1. NMR CDCl₃: H, 7a, d 5.28 s, 5H, C₅H₅,

5

Ž

.

Ž

.

(

)]

7

h -C₅H₅

An excess of sodium borohydride 0.02 g, 0.529

mmol was added to a solution of 4 0.10 g, 0.349

mmol in methanol 10 ml , and the mixture was stirred

at ambient temperature for 30 h. Monitoring by TLC

showed the formation of a new product R_fs0.9,

c

e

c

b

w

Ž

.

Ž

.

Ž

4.18 ddd, 1H, H , J H H

11.4, J H H

7.7,

.

c

d

b

a

Ž

.

x

Ž

.

Ž

.

Ž

J H H 7.6 , 3.78 m, 1H, H , 3.62 m, 1H, H ,

d

c

Ž

.

w

Ž

.

Ž

.

3.25 s, 3H, OMe , 2.95 dd, 1H, H , J H H 7.6,

d

e

d

Ž

.

x

w

Ž

.

x

J H H 2.4 and 1.38 dd, 1H, H , J H H 2.4 .

Ž

.

Ž

.

aluminarCH₂Cl₂. Water 0.5 ml was added and the

mixture was stirred for 0.5 h, after which the solvents

were removed in vacuo. The yellow residue was ex-

tracted with several portions of Et₂O, which were con-

centrated to an oil under reduced pressure and redis-

solved in a small volume of hexane, before being

chromatographed on alumina. Elution with hexane af-

forded a yellow band which gave, after removal of

1

c

Ž

.

Ž

.

a

H, 7b, d 5.28 s, 5H, C₅H₅, 4.18 m, 1H, H , 3.78

b

a

f

b

Ž

.

Ž

.

w

Ž

.

Ž

.

solvent and recrystallisation from hexane y308C , yel-

m, 1H, H , 3.64 dd, 1H, H , J H H 10.9, J H H

d

c

Ž

. Ž

x

Ž

.

w

Ž

.

low crystals of 7 0.073 g, 69% Found: C, 47.6; H, 4.7

3.7 , 3.25 s, 3H, OMe , 2.95 dt, 1H, H , J H H 7.6,

d

f

b

.

Ž

.

Ž

.

x

w

Ž

.

C₁₂H₁₄MoO₃requires C, 47.7; H, 4.7% . IR CH₂Cl₂:

y CO 1948 vs and 1863 cm . NMR CD₂Cl₂: H, d

5.30 s, 5H, C₅H₅, 4.21 ddd, 1H, H , J H H 11.4,

J H D 2.4 and 1.85 dd, 1H, H , J H H 11.1,

J H H 10.9 .

1

y1

f

a

Ž

.

Ž

.

x

c

e

Ž

.

w

Ž

.

c

b

f

c

d

c

b

Ž

.

Ž

. x

w

J H H

7.7, J H H

7.6 , 3.77 dddd, 1H, H ,

b

a

b

d

Ž

.

Ž

.

Ž

b

.

x

J H H 11.2, J H H 7.7, J H H 3.7, J H H

1.6 , 3.62 dd, 1H, H , J H H 11.0, J H H 3.7 ,

3.21 s, 3H, OMe , 2.96 ddd, 1H, H , J H H 11.2,

J H H 11.0 and 1.35 dd, 1H, H , J H H 11.4,

a

f

a

x

w

Ž

.

b

f

Ž

.

w

.

c

f

a

c

e

Ž

.

x

w

Ž

.

13

e

d

x

Ä¹

Ž

4

.

Ž

.

Ž

.

J H H 2.4 ; C- H , d 237.5, CO , 237.0 CO ,

1

3

Ž

.

Ž

.

Ž

.

92.0 C₅H₅, 71.7 C , 67.1 C , 57.2 OMe , 53.9

2

4

w x^qx^q

and 38.0 C . FAB MS, M 304, M–OMe

w

13

Ä¹

4

Ž

.

3

Ž

.

Ž

.

Ž

.

C

C- H for 7a and 7b, d 237.6 CO , 237.1 CO ,

w

x^qx^q

w

1

245, M–OMe–CO 245, M–OMe–2CO 217.

Ž

.

Ž

.

Ž

.

Ž

.

91.7 C₅H₅, 71.8 br s. C , 66.6 C , 57.6 OMe ,

53.4 C and 38.1 br s, C .

2

4

Ž

.

Ž

.

3

5

[

)]

{

(

)( ) (

3.2.1. Mo h -exo-anti-CH₂CHCHCH₂OH CO ₂h -

C₅Me₅

8

Ž

.

Sodium borohydride 0.013 g, 0.321 mmol was

added to a solution of the yellow complex 2 0.104 g,

0.292 mmol in methanol 10 ml , and the mixture was

Ž

.

Ž

.

(

)

278

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

Ž

.

w

x^q

w

stirred at ambient temperature for 1 h. Monitoring by

infrared spectroscopy indicated the complete consump-

tion of starting material and the formation of a new

10.3 C₅Me . FAB MS, M–OMe 343, M–OMe–

x^q

w⁵

x^q

CO 315, M–OMe–2CO 287.

3.3. Formation of 8 by protonation of 2 followed by

nucleophilic attack

Ž

.

product. Water 0.5 ml was added, and the mixture was

stirred for 0.5 h before the solvents were removed in

vacuo. The yellow residue was extracted with several

portions of Et₂O, which were concentrated to a small

volume under reduced pressure and chromatographed

on alumina. Elution with Et₂O afforded a yellow band

which gave, after removal of solvent and recrystallisa-

tion from CH₂Cl₂rhexane, afforded yellow crystals of

Ž .

Ž

.

a A solution of 2 0.104 g, 0.292 mmol in CH₂Cl₂

Ž

.

15 ml was cooled to y788C and treated with HBF₄P

Ž

Et₂O 0.10 g, 0.09 ml of an 85% Et₂O solution, 1.05

.

mmol causing a slight darkening in colour. The mix-

ture was allowed to warm to room temperature and

stirred for 1 h. The resulting orange solution was fil-

tered through Celite and then concentrated to a small

volume 3 ml under vacuo. Addition of Et₂O precipi-

tated an orange solid, which was washed with Et₂O and

Ž

. Ž

8 0.065 g, 62% Found: C. 53.3; H, 6.0. C₁₆H₂₂MoO₃

.

Ž

.

Ž

.

Ž

.

requires C, 53.6; H, 6.2% . IR CH₂Cl₂: y CO 1935

1

vs and 1852 s cm^y1. NMR CD₂Cl : H, d 3.64 dd,

Ž

w

²x

w

a

t

a

b

Ž

.

Ž

.

1H, H . J H H 11.4, J H H 3.6 , 3.22 ddddd,1H,

recrystallised from CH₂Cl₂rEt₂O to afford orange

H^b, J H H

11.2, J H H

7.6, J H H

3.6,

b

f

b

c

b

a

4

Ž

.

Ž

.

Ž

.

w

ÄŽ

crystals of Mo h -exo-syn-s-cis-CH ₂CHCHCH-

b

d

c

b

e

c

5

Ž

.

Ž

.

x

w

Ž

.

4

Ž

. Ž .

.

xw

x

Ž

J H H

1.5, J H H

0.6 , 2.85 ddd, 1H, H ,

OH CO h -C₅Me₅BF₄10 0.111 g, 86%

2

c

d

c

b

Ž

.

Ž

.

Ž

.

x

w

J H H 11.9, J H H J H H 7.6 , 2.25 ddd, 1H,

Found: C, 43.5; H,4.5. C₁₆H₂₁BF₄MoO₃requires C,

d

c

d

e

d

b

Ž

.

Ž

.

Ž

.

x

.

Ž

.

Ž

.

H , J H H 7.6, J H H 2.4, J H H 1.5 , 2.07

43.2; H,4.7% . IR CH₂Cl₂: y CO 1993 vs and 1927

1

f

a

f

b

a

vs cm^y1. NMR CD₂Cl₂: H, d 5.67 d, 1H, H ,

w

Ž

.

Ž

.

x

Ž

w

dd, 1H, H , J H H 11.4, J H H 11.2 , 1.86 s,

a

b

a

b

c

.

Ž

.

w

Ž

.

x

w

Ž

.

Ž

.

15H, C₅Me₅, 1.51 br s, 1H, OH and 1.46 ddd, 1H,

J H H 9.3 , 4.30 dd, 1H, H , J H H 9.3, J H H

6.3 , 4.11 ddd, 1H, H , J H H 6.3, J H H 8.6,

J H H 11.6 , 2.20 d, 1H, H , J H H 8.6 , 1.41 d,

H , J H H 11.9, J H H 2.4, J H H 0.6 ; ¹³C-

e

c

e

d

e

b

c

b

c

d

Ž

.

Ž

.

x

w

Ž

.

Ž

.

Ä¹

Ž

4

.

Ž

.

Ž

.

Ž

.

c

e

d

c

d

Ž

.

x

w

.

x

w

H , d 240.3 CO , 239.8 CO , 103.9 C₅Me₅, 74.0

C , 62.4 C , 61.8 C , 41.9 C and 10.3 C₅Me₅.

FAB MS, MH 359, M–2H–2CO 330, M–2H–

2CO 302.

3

1

2

4

e

c

e

Ž

w

.

Ž

.

Ž

.

Ž

.

x

1H, H , J H H 11.6 .

x^q

w

x^q

w

Ž .

Ž

b Sodium cyanoborohydride 0.249 ml of a 1 M

x^q

.

solution in thf, 0.249 mmol was added to a cooled

08C suspension of the cation 10 0.110 g, 0.249 mmol

Ž

.

Ž

.

3

[

{

(

)

}

(

)

2

Ž

.

3.2.2. Mo h -exo-anti-CH₂CHCHCH₂OMe CO -

in thf 20 ml . The reaction mixture was stirred for 1 h

at 08C before being allowed to warm to ambient temper-

ature. After stirring, the yellow solution for 1 h at room

temperature, the solvent was removed in vacuo, and the

residue was chromatographed on alumina. Elution with

Et₂O afforded a yellow fraction which gave, after re-

moval of solvent and recrystallisation from

CH₂Cl₂rhexane, yellow crystals of 8 0.090 g, 85% ,

identified by comparison of the IR and NMR spectra of

an authentic sample.

5

(

)]

9

h -C₅Me₅

An excess of sodium borohydride 0.021 g, 0.544

Ž

.

mmol was added to a solution of 2 0.097 g, 0.272

mmol in methanol 10 cm , and the mixture was

stirred at ambient temperature for 2 d. Monitoring by

TLC showed the formation of a new product R_fs0.92,

3

Ž

.

Ž

3

.

Ž

.

Ž

.

aluminarCH₂Cl₂. Water 0.5 cm was added, and the

mixture was stirred for 0.5 h, after which the solvents

were removed in vacuo. The yellow residue was ex-

tracted with several portions of Et₂O, which were con-

centrated to an oil under reduced pressure and redis-

solved in a small volume of hexane, before being

chromatographed on alumina. Elution with hexane af-

forded a yellow band which gave, after removal of

3.4. Oxidation of 6 to form the aldehyde complex 4

Ž

.

Morpholine-N-oxide 0.274 g, 2.34 mmol was added

to a solution of 6 0.450 g, 1.56 mmol in CH₂Cl₂5

ml which contained 4 A molecular sieves. After stir-

ring at room temperature for 10 min, Bu₄N RuO₄

0.027 g, 0.078 mmol was added. The reaction was

monitored by IR spectroscopy and was complete after

10 h. The reaction mixture was diluted with CH₂Cl₂

50 ml and washed with sodium sulphite solution 0.5

M, 10 ml , and NaCl 0.5 M, 10 ml . The organic layer

Ž

.

Ž

˚

.

n

Ž

. Ž

.

w

xw x

solvent and recrystallisation from hexane y308C , af-

Ž

.

forded yellow crystals of 9 0.066 g, 65% Found: C,

.

54.4; H, 6.7. C₁₇H₂₄MoO₃requires C, 54.8; H, 6.5% .

IR CH₂Cl₂: y CO 1935 vs and 1850 s cm^y1. NMR

Ž

.

Ž

.

1

a

f

Ž

.

w

Ž

.

Ž

.

Ž

CD₂Cl₂: H, d 3.56 dd, 1H, H , J H H 10.9,

J H H 3.6 , 3.20 s, 3H, OMe , 3.05 dddd, 1H, H ,

J H H 11.1, J H H 7.8, J H H 3.6, J H H

1.6 , 2.92 ddd, 1H, H , J H H 11.2, J H H 7.8,

7.5 , 2.25 ddd, 1H, H , J H H 7.5,

J H H 2.4, J H H 1.6 , 1.86 s, 15H, C Me₅,

a

b

Ž

x

Ž

.

w

.

Ž

.

b

f

b

c

b

a

b

d

Ž

.

Ž

.

Ž

.

Ž

.

was dried Na₂SO₄and the volatile material removed

in vacuo. The residue was extracted with CH₂Cl₂10

ml and filtered through a small pad of alumina, the

c

e

c

b

x

w

Ž

.

Ž

.

c

Ž

c

d

e

d

Ž

.

x

w

Ž

.

J H H

d

b

Ž

.

x

Ž

.

volume reduced in vacuo to 3 ml and chromatographed

on alumina. Elution with CH₂Cl₂gave a single yellow

band, which, on recrystallisation from CH₂Cl₂rhexane,

w

Ž

.

Ž

.

⁵x

f

b

f

a

1.80 dd, 1H, H , J H H 11.1, J H H 10.9 and

1.43 dd, 1H, H , J H H 11.2, J H H 2.4 ; ¹³C-

e

c

e

d

w

.

Ž

x

Ä¹

Ž

4

.

Ž

.

Ž

.

Ž

.

Ž

.

H , d 240.6 CO , 240.0 CO , 103.9 C₅Me₅, 75.2

afforded bright yellow crystals of 4 0.268 g, 60%

3

1

2

4

Ž

.

Ž

.

Ž

.

Ž

.

C , 72.0 C , 57.9 C , 57.0 OMe , 41.8 C and

identified by IR and NMR spectroscopy.

(

)

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

279

An identical procedure was followed for the conver-

sion of 8 into 2.

being chromatographed on alumina. Elution with hex-

ane afforded a major yellow fraction which gave, after

removal of solvent and recrystallisation from hexane,

3

[

{

(

)

}

(

)

3.4.1. Mo h -exo-anti-CH₂CHCHCH OH Me CO ₂-

Ž

. Ž

yellow crystals of 12 0.110 g, 53% Found: C, 49.4;

5

(

)]

h -C₅H₅11

Methylmagnesium iodide 2.10 ml of a 3.0 M solu-

.

H, 5.1. C₁₃H₁₆MoO₃requires C, 49.4; H, 5.1% . IR

Ž

CH₂Cl₂: y CO 1941 vs and 1850 s cm^y1. NMR

Ž

.

Ž

.

Ž

.

1

tion in thf, 6.29 mmol was added to a cooled y208C

c

Ž

.

Ž

.

w

CDCl₃: H d 5.28 s, 5H, C₅H₅_c, 4.00 ddd, 1H, H ,

Ž

.

solution of the yellow complex 4 1.44 g, 5.03 mmol in

c

e

c

b

d

Ž

.

Ž

.

Ž

.

x

w

J H H 11.6, J H H 8.1, J H H 7.9 , 3.79 ddd,

Ž

.

thf 50 ml . The mixture was allowed to warm to

ambient temperature and stirred for 2 h. Monitoring by

infrared spectroscopy indicated that the reaction had

gone to completion. The mixture was quenched with

b

a

b

d

Ž

.

Ž

.

x

w

1H, H , J H H 8.5, J H H 1.9 , 3.05 ddd, 1H,

d

c

d

e

d

b

Ž

.

Ž

.

Ž

.

x

H , J H H 7.9, J H H 2.1, J H H 1.9 , 2.63

m, 1H, H , 2.47 d, 1H, OH, J OH, H 3.1 , 1.66–

1.46 m, 2H, CH₂, 1.41 dd, 1H, H , J H H 11.6,

J H H 2.1 and 0.90 t, 3H, CH₃, J CH₃CH₂7.4 ;

a

Ž

.

w

Ž

.

x

e

c

Ž

.

w

Ž

.

Ž

.

water 1 ml and stirred for a further 0.5 h, causing the

mixture to turn red-brown in colour. The solvents were

removed in vacuo and the residue extracted with CH₂Cl₂

and filtered through a small pad of alumina. The red

filtrate was concentrated to a small volume under re-

duced pressure before being chromatographed on alu-

mina. Elution with CH₂Cl₂afforded a major yellow

fraction which gave, after removal of solvent and re-

crystallisation from CH₂Cl₂rhexane, yellow crystals of

e

d

Ž

.

x

w

Ž

.

x

13

Ä¹

.

4

Ž

.

Ž

.

Ž

.

C- H , d 241.4 CO , 236.4 CO , 91.9 C₅H₅, 75.2

1

3

2

4

Ž

.

Ž

.

Ž

.

Ž

.

C , 66.9 C , 65.2 C , 40.9 C , 36.2 CH₂and

Ž

.

w x^q

w

x^q

w

10.2 Me . FAB MS, M 318, M–OH 301, M–

x^q

w

x^q

OH–CO 273 and M–OH–2CO 245.

3

[

{

(

)

}

(

)

3.4.3. Mo h -exo-anti-CH₂CHCHCH OH Ph CO ₂-

5

(

)]

h -C₅H₅13

Phenylmagnesium chloride 0.70 ml of a 2.0 M

Ž

.

Ž

.

Ž

. Ž

solution in thf, 1.40 mmol was added to a cooled 08C

11 1.07 g, 70% Found: C, 47.2; H, 4.6. C₁₂H₁₄MoO₃

Ž

.

Ž

.

Ž

.

Ž

.

solution of 4 0.20 g, 0.66 mmol in thf 20 ml . The

mixture was allowed to warm to ambient temperature

and stirred for 2 h. Monitoring by infrared spectroscopy

indicated that the reaction had gone to completion. The

requires C, 47.7; H, 4.7% . IR CH₂₁Cl₂: y CO 1943

vs and 1850 cm^y1. NMR CD₂Cl₂: H, d 5.30 s, 5H,

Ž

.

Ž

c

e

c

b

.

w

Ž

.

Ž

.

C₅H₅, 4.01 ddd, 1H, H , J H H 11.7, J H H

c

d

c

b

a

Ž

.

x

w

Ž

.

J H H

7.9 , 3.82 ddd, 1H, H , J H H 8.3,

7.9, J H H

J H H 7.9, J H H 2.0, J H H 1.8 , 2.89 dqd,

1H, H , J H H 8.3, J H Me 6.2, J H OH 3.3 ,

2.35 d, 1H, OH, J H OH 3.3 , 1.44 dd, 1H, H ,

J H H 11.7, J H H 2.0 and 1.18 d, 1H, Me,

J MeH 6.2 ; C- H . d 242.5 CO , 237.6 CO ,

b

d

Ž

.

Ž

. x

w

b

mixture was quenched with water 0.5 ml and stirred

for a further 0.5 h at room temperature. Solvents were

removed in vacuo and the residue extracted with Et₂O

and filtered through Celite. The filtrate was concen-

trated to an oily residue under reduced pressure and

chromatographed on alumina. Elution with hexane gave,

after removal of solvent and recrystallisation from hex-

1.8 , 3.04 ddd, 1H, H ,

d

e

d

Ž

.

Ž

.

x

a

w

a

b

a

Ž

.

Ž

.

x

Ž

w

.

x

a

e

w

Ž

.

e

c

d

Ž

.

Ž

.

x

w

13

a

x

Ä¹

4

Ž

.

Ž

.

1

3

2

4

Ž

.

Ž

.

Ž

.

Ž

92.2 C₅H₅, 70.5 C , 68.5 C , 65.2 C , 40.8 C

w x^q

w

x^q

Ž

. Ž

Ž

.

ane, yellow crystals of 13 0.014 g, 57% Found: C,

and 29.3 Me . FAB MS M 304, M–OH 287,

.

w

x^q

w

x^q

56.7; H, 4.1, C₁₇H₁₆MoO₃requires C, 56.1; H, 4.4% .

M–OH–CO 259, and M–OH–2CO 231.

IR CH₂Cl₂: y CO 1946 vs and 1858 s cm^y1. NMR

Ž

.

Ž

.

1

Ž

.

Ž

.

Ž

CDCl₃: H, d 7.31–7.18 m, 5H, C₆H₅, 5.24 s, 5H,

C₅H₅, 4.01 ddd, 1H, H . J H H 8.9. J H H 8.4,

b

a

b c

.

w

Ž

.

Ž

.

b

d

b

c

e

Ž

.

x w Ž

.

J H H

1.8 , 3.85 ddd, 1H, H , J H H 11.7,

c

d

a

b

Ž

.

x

w

Ž

c

.

J H H 8.4, J H H 7.9 , 3.67 dd, 1H, H , J H H

a

d

Ž

.

x

w

Ž

.

8.9, J H OH 2.9 , 3.04 ddd, 1H, H , J H H 7.9,

d

c

d

b

a

Ž

.

Ž

.

x

w

Ž

.

J H H 2.2, J H H 1.8 , 2.61 d, 1H, OH, J OH,H

e

c

e

d

x

w

Ž

.

Ž

2.9 and 1.58 dd, 1H, H , J H H 11.7, J H H

13

5

6

10

x

Ä¹

4

Ž

.

Ž

.

2.2 ; C- H , d 147.5 C , 128.4 C and C , 127.3

3

[

{

(

)

}

(

)

2

3.4.2. Mo h -exo-anti-CH₂CHCHCH OH Et CO -

7

9

8

1

Ž

w

.

Ž

.

Ž

.

C and C , 125.5 C , 91.9 C₅H₅, 75.7 C , 66.8

5

(

)]

h -C₅H₅12

3

2

4

.

Ž

w x^q

C , 65.1 C and 42.3 C . FAB MS, M 366,

Ž

Ethylmagnesium bromide 0.46 ml of a 3.0 M solu-

tion in Et₂O, 1.38 mmol was added to a cooled 08C

x^q

M–OH 349.

.

Ž

.

Ž

.

Ž

.

solution of 4 0.20 g, 0.66 mmol in thf 20 ml . The

mixture was allowed to warm to ambient temperature

and stirred for 2 h. Monitoring by infrared spectroscopy

indicated that the reaction had gone to completion. The

mixture was quenched with water 1 ml and stirred for

a further 0.5 h at room temperature. Solvents were

removed in vacuo and the residue extracted with Et₂O

and filtered through Celite. The filtrate was concen-

trated to an oily residue under reduced pressure before

Ž

.

(

)

280

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

3

f

g

c

g

b

a

[

{

)]

(

)

}

(

)

Ž

.

x

w

Ž

.

3.4.4. Mo h -exo-anti-CH₂CHCHCH OH Me CO ₂-

J H H

1.6 , 4.50 ddd, 1H, H , J H H 10.1,

5

b

d

f

a

(

Ž

.

x

w

h -C₅Me₅14

Methyllithium 0.305 ml of a 1.4 M solution in Et₂O,

J H H

7.7, J H H

1.4 , 4.33 ddd, 1H, H ,

a

a b

Ž

.

Ž

.

x

c

J H H 16.2, J H H 10.3, J H H 10.1 , 4.19

c

e

c

b

d

.

Ž

.

w

Ž

.

Ž

.

Ž

e

.

0.427 mmol was added to a cooled y788C solution

ddd, 1H, H , J H H 11.5, J H H 7.7, J H H

d

c

d

Ž

.

Ž

.

x

w

Ž

.

Ž

.

c

of 2 0.117 g, 0.328 mmol in thf 10 ml . The mixture

was stirred at y788C for 1 h and at ambient tempera-

ture for 15 h, during which time the colour of the

7.5 , 2.84 ddd, 1H, H , J H H 7.5, J H H 2.5,

d

b

e

Ž

.

x

w

Ž

.

J H H 1.4 and 1.47 dd, 1H, H , J H H 11.5,

13

e

d

x

Ä¹

4

Ž

.

Ž

.

J H H 2.5 ; C- H , d 237.6 CO , 236.6 CO ,

1

5

3

Ž

.

Ž

.

Ž

.

Ž

w

.

solution turned red. An excess of water 0.060 ml, 3.28

mmol was added and the mixture stirred for a further 2

134.8 C , 110.8 C , 91.7 C H₅, 66.5 C , 64.6

w⁵x^q

x^q

and 34.7, C . FAB MS, MH 287, M–CO

2

4

.

Ž

.

Ž

.

C

w

x^q

258 and M–2CO 230.

h at room temperature. The solvents were removed in

vacuo and the orange-red residue was extracted with

CH₂Cl₂and filtered through Celite. The orange filtrate

was reduced to a small volume under reduced pressure

before being chromatographed on alumina. Elution with

Ž

.

hexane and then CH₂Cl₂rhexane 1:3 afforded a yel-

low fraction which gave, after removal of solvent and

Ž

.

recrystallisation from pentane y358C , yellow crystals

Ž

.Ž

of 14 0.092 g, 75% Found: C, 54.6; H, 6.4.

.

Ž

.

C₁₇₁H₂₄MoO₃requires C, 54.8; H, 6.5% . IR CH₂₁Cl₂:

y1

Ž

.

y CO 1929 vs and 1836 s cm . NMR CD₂Cl_2c: H, d

b

a

b

w

Ž

.

Ž

.

3.12 dddd, 1H, H , J H H

8.2, J H H 7.8,

. x w

0.7 , 2.87 dqd, 1H, H ,

b

d

b

e

a

Ž

.

Ž

J H H

1.7, J H H

a

Ž

.

Ž

.

x

w

J H H 8.2, J H Me 6.1, J H OH 3.2 , 2.71 ddd,

1H, H . J H H 11.7, J H H 8.4, J H H 7.8 ,

2.32 ddd, 1H, H , J H H

J H H 1.7 , 1.86 s, 15H, C₅Me₅, 1.53 ddd, 1H,

H , J H H 11.7, J H H 2.2, J H H 0.7 and

1.41 d, 3H, Me, J MeH 6.1 ; C- H , d 245.6

CO , 239.8 CO , 104.0 C₅Me₅, 73.5, 73.4 C and

C , 71.0 C , 43.7 C , 28.9 Me and 10.3 C₅Me₅.

c

e

c

d

c

b

Ž

.

Ž

.

Ž

.

x

d

c

d

e

w

Ž

.

Ž

8.4, J H H

2.2,

d

b

Ž

.

x

Ž

.

Ž

w

b

[

][ ]

3.6. Reaction of 4 with NO BF₄

e

c

e

c

d

e

Ž

w

.

Ž

.

x

13

a

Ž

.

x

Ä¹

4

1

Ž

.

Ž

.

Ž

.

Ž

.

Complex 4 0.05 g, 0.16 mmol was dissolved in

xw

3

2

4

.

Ž

.

Ž

.

Ž

.

Ž

.

w

x

acetonitrile 15 ml and cooled to 08C. Solid NO BF₄

Ž

.

0.02 g, 0.19 mmol was added, and after stirring for

0.25 h, the solvent was removed in vacuo from a

sample, and the IR spectrum recorded in CH₂Cl₂. The

3

[

{

3.5. Attempted Oppenauer oxidation of Mo h -exo-

y1

Ž

.

spectrum showed y NO bands at 2072 and 1721 cm

,

5

(

)

}

(

) (

)]

anti-CH₂CHCHCH OH Me CO ₂h -C₅H₅11

Ž

.

respectively. An excess of Na₂CO₃1.0 g was then

added to the remainder of the acetonitrile solution and

stirring continued for 4 h at room temperature. The

solvent was removed in vacuo, and the residue extracted

into dichloromethane. Chromatography on alumina and

Ž

.

An excess of dry acetone 15 ml, 204 mmol was

Ž

added to a solution of the yellow complex 11 0.70 g,

2.32 mmol in toluene 37 ml . To this was added

.

Ž

.

Ž

.

Ž

.

aluminium tri-isopropoxide 1.42 g, 6.95 mmol and the

mixture was heated to reflux for 5.5 h. Monitoring by

infrared spectroscopy and TLC indicated the formation

of a new compound. After cooling to ambient tempera-

ture, the solvent was removed in vacuo and the yellow

residue was extracted with CH₂Cl₂. The organic ex-

tracts were combined and concentrated to an oil before

being chromatographed on alumina. Elution with hex-

elution with CH₂Cl₂rhexane 1:2 afforded a single

yellow band that was collected. Removal of the solvent

2

w

Ä

in vacuo gave a yellow low melting solid Mo h -

5

Ž .

4

Ž

.Ž

x

Ž

H Me CO NO h -C₅H₅16 0.030

y1

.

Ž

.

Ž

.

Ž

.

g, 62% . IR CH₂Cl₂: y CO 1975, y NO 1622 cm

NMR CD₂Cl₂: H major product exo d 5.72 dq,

.

1

Ž

.

Ž

.

w

a

b

a

Ž

.

Ž

.

x

Ž

1H, H , J H H 15.1, J H Me 6.7 , 5.55 s, 5H,

b

a

b

c

.

w

Ž

.

Ž

.

C₅H₅, 5.09 ddq, 1H, H , J H H 15.1, J H H

b

c

d

Ž

.

Ž . x w Ž

.

c

ane–CH₂Cl₂5:1 afforded a major yellow fraction

which gave, after removal of solvent and recrystallisa-

11.6, J H Me 1.5 , 3.97 ddd, 1H, H , J H H 10.8,

c

e

d

Ž

.

x

w

Ž

.

c

J H H 10.8 , 2.46 dd, 1H, H , J H H

10.8,

3

d

e

Ž

.

w

Ä

Ž

.

x

w

.

tion from hexane y308C , yellow crystals of Mo h -

J H H

1.9 , 2.30 dd, 1H, H , J H H

J H H 1.9 , 1.70 d, 3H, Me, J MeH 6.7, J MeH

1.5 ; minor product endo d 5.78 dq, 1H, H , J H H

15.1, J H Me 6.7 , 5.53 s, 5H, C H₅, 5.00 ddq, 1H,

5

e

d

a

b

Ž

.

4

Ž

. Ž

.

x

Ž

.

x

w

Ž

w

.

Ž

.

exo-anti-CH ₂CHCH CHCH ₂CO h -C₅H₅

15

0.31 g, 47% Found: C, 50.4; H, 4.2. C₁₂H₁₂MoO₂

2

a

b

Ž

. Ž

x

Ž

.

Ž

a

.

Ž

.

Ž

.

Ž

.

x

Ž

.

w

requires C, 50.7; H, 4.3% . IR CH₂Cl₂: y CO 1950 s

and 1867 s, y C5C 1617 m cm , NMR CH₂Cl₂:

H, d 5.29 s, 5H, C₅H₅, 4.99 dd, 1H, H , J H H

16.2, J H H 1.6 , 4.72 dd, 1H, H , J H H 10.3,

x⁵

w

y1

b

a

b

c

Ž

.

Ž

.

Ž

.

Ž

.

H , J H H 12.0, J H Me 1.5 , 3.61 ddd, 1H, H ,

1

g

a

c

b

c

d

c

e

Ž

.

w

Ž

.

Ž

.

Ž

.

Ž

.

x

w

J H H 12.0 J H H 9.8, J H H 9.8 , 2.34 dd,

g

f

a

d

c

d

e

Ž

.

x

w

Ž

.

Ž . Ž . x w

1H, H , J H H 9.8, J H H 1.6 , 1.93 dd, 1H, H ,

Table 7

Crystallographic details for compounds 2^a, 7 and 15

Complex

2

7

15

Empirical formula

Formula weight

Crystal size

C₁₆H₂₀MoO₃

356.26

0.2=0.2=0.2 mm

P2₁rn

Ž .

10.919 2

C₁₂H₁₄MoO₃

302.17

0.4=0.4=0.3 mm

P2₁rc

Ž .

8.338 2

C₁₂H₁₂MoO₂

284.16

0.2=0.2=0.2 mm

P2₁rc

Ž .

9.001 1

Space group

˚

Ž .

a A

˚

Ž .

b A

Ž .

10.578 2

Ž .

7.511 2

Ž .

8.699 1

˚

Ž .

90.18 2

Ž .

98.34 2

Ž .

14.522 2

c A

13.724 2

19.661 6

Ž .

101.25 1

b 8

3

˚

Ž .

Ž

.

Ž .

U A

1585.1 5 A

1218.3 6 A

1115.2 2 A

D_cg cm

1.493 Mgrm³

1.647 Mgrm³

1.692 Mgrm³

y3

Ž

.

. Ž

y1

Ž

.

m MoyK_amm

0.831

728

1.065

608

1.152

568

.

F 000

Crystal dimensions mm

Ž .

Ž

.

0.2=0.2=0.2

0.4=0.4=0.3

0.2=0.2=0.2

2–24

u range 8

2–22

2–24

Index ranges

No. data collected

0FhF11; y11FkF0; y14FlF14

0FhF9; 0FkF8; y22FlF22

y10FhF0; 0FkF9; y16FlF16

2054

1583

2060

1715

1868

1489

Ž .

No. reflections with I)2s I

Independent reflections

Absorption correction

Maximum, minimum absorption

corrections

w

Ž

.

x

w

Ž

.

x

w

Ž

.

x

1932 R int s0.0197

1914 R int s0.0253

1748 R int s0.0192

y

DIFABS

y

1.187, 0.714

Datarrestraintsrparameters

1928r0r241

0.991

1914r4r160

1.191

1748r11r174

0.859

Goodness-of-fit on F²

w

Ž .x

R1, wR2 I)2s I

0.0393, 0.1218

0.0514, 0.1295

0.458, y0.462

0.0343, 0.1266

0.0385, 0.1298

0.838, y0.825

0.0317, 0.0921

0.0407, 0.0972

0.891, y0.886

Ž

.

R1, wR2 all data

Maximum, minimum residual

y3

˚

Ž

.

electron density e A

Weighting scheme

2

w

²Ž

.

Ž

.

x

w

²Ž

.

Ž

.²x

w

²Ž

.

Ž

2

.²x

ws1r s F_oq 0.0752 P q5.1908P

ws1r s F_oq 0.1000P

2

Ž

.

Ž

.

Ž .

where Ps F_oq2F_cr3

Ž .

Ž

.

Ž .

0.0029 10

Extinction coefficient

0.0052 9

0.0015 12

a

2

c

3

x^y1r4

˚

Ž

.

w

Details in common: l Mo–K_a0.70930 A; T s293 K; Zs4; Ext. expression F_cskF 1q0.001 F l rsin2Q

c

(

)

282

C.J. Beddows et al.rJournal of Organometallic Chemistry 550 1998 267–282

e

c

e

d

a

Ž

.

Ž

.

x

w

Ž

.

J H H 9.8, J H H 1.6 , 1.80 dd, 3H, Me, J MeH

References

b

Ž

.

x

w x^q

w

x^q

6.7, J MeH 1.5 , FAB MS, M 303, M–CO 275.

w x

1

A.J. Pearson, Recent Developments in the Synthetic Applica-

tions of Organoiron and Organomolybdenum Chemistry, in:

Ž

.

L.S. Liebeskind Ed. , Adv. in Metal-Organic Chem., JAI Press,

London, 1989, Vol. 1, p. 1.

w x

Ž .

2

w x

3

A.J. Pearson, Synlett 1990 , 10.

Ž

.

A.J. Pearson, Cyclohexadienes, in: M. Sainsbury Ed. , Second

Supplements to the 2nd edition of Rodd’s Chemistry of Carbon

Compounds, Vols. IIA and B, Elsevier, Amsterdam, 1992, p.

447.

w x

4

W.-J. Vong, S.-M. Peng, S.-H. Lin, W.-J. Lin, R.-S. Liu, J. Am.

Ž

.

Chem. Soc. 113 1991 573.

w x

5

S.-H. Lin, G.-H. Lee, S.-M. Peng, R.-S. Liu, Organometallics

Ž

.

12 1993 2591.

3.7. Crystallography

w x

6

S.A. Benyunes, A. Binelli, M. Green, M.J. Grimshire, J. Chem.

Ž

.

Soc., Dalton Trans. 1991 895.

w x

7

S.A. Benyunes, M. Green, M.J. Grimshire, Organometallics 8

3.7.1. Crystal structure determinations

Ž

.

1989 2268.

Many of the details of the structure analyses carried

out on compounds 2, 7 and 15 are listed in Table 7.

Data collections were carried out on a CAD4 diffrac-

tometer, and corrections for Lorentz and polarisation

effects were applied in all cases. The structures were

solved by Patterson methods and refined using the

w x

8

Ž

.

M. Bottrill, M. Green, J. Chem. Soc., Dalton Trans. 1977

2365.

w x

9

V.V. Krivykh, O.V. Gusev, M.I. Rybinskay, J. Organomet.

Ž

.

Chem. 362 1989 351.

w

x

10 A.G. Orpen, L. Brammer, E.H. Allen, O. Kennard, D.G. Wat-

Ž

.

son, R. Taylor, J. Chem. Soc., Dalton Trans. 1989 S1.

x

11 J.W. Faller, H.H. Murray, D.L. White, K.H. Chao,

w

x

SHELX suite of programs 22–24 . Structural diagrams

Ž

.

Organometallics 2 1983 400.

w

x

were generated using ORTEX 25 . Non-hydrogen atoms

were refined anisotropically for all 3 compounds.

It became evident that there was some disorder at an

early stage in the refinement of 2, both of the allyl

methoxy fragment and of the carbonyls. Typically, O1,

O2, O3, C11, C12 and C16 were seen to be disordered

with their primed equivalents in the ratio 70:30. Only

the major structure is illustrated in the molecular plot.

All hydrogen atoms were located in 15 and refined at

x

12 J.W. Faller, D.F. Chodosh, D. Katahira, J. Organomet. Chem.

Ž

.

187 1980 227.

x

13 M. Green, S. Greenfield, M. Kersting, J. Chem. Soc., Chem.

Ž

.

Commun. 1985 18.

x

14 S. Hansson, J.F. Miller, L.S. Liebeskind, J. Am. Chem. Soc.

Ž

.

112 1990 9660.

w

x

Ž

.

15 A. Rubio, L.S. Liebeskind, J. Am. Chem. Soc. 115 1993 891.

x

16 W.P. Griffiths, S.V. Ley, G.P. Whitcombe, A.D. White, Chem.

Ž

.

J. Soc., Chem. Commun. 1987 1625.

w

x

17 D. Schinzer, H. Barmann, Angew. Chem., Int. Ed. Engl. 35

¨

Ž

.

1996 1678.

˚

a fixed distance of 0.98 A from the relevant parent

x

18 S.A. Benyunes, R.J. Deeth, A. Fries, M. Green, M. McPartlin,

Ž

atoms as were H8A, H8B, H91 and H101 attached to

Ž

.

C.B.M. Nation, J. Chem. Soc., Dalton Trans. 1992 3453.

.

x

C8, C9 and C10 in 7. The remaining hydrogens in the

19 T.-C. Yueh, S.-F. Lush, G.-H. Lee, S.-M. Peng, R.-S. Liu,

latter complex, and those associated with the h⁵-C₅Me₅

ring in 2 were included at calculated positions. Location

of the hydrogens on the oxyallyl ligand in 2 was

precluded by the disorder.

Ž

.

Organometallics 15 1996 5669.

w

x

Ž

.

20 J.W. Faller, A.M. Rosan, J. Am. Chem. Soc. 98 1976 3388.

x

21 B.E.R. Schilling, R. Hoffmann, J.W. Faller, J. Am. Chem. Soc.

Ž

.

101 1979 592.

w

x

Ž

.

22 G.M. Sheldrick, Acta Crystallogr., Sect. A 1990 467.

x

23 G.M. Sheldrick, SHELX 76, a computer programme for crystal

structure determination, Univ. of Cambridge, 1976.

w

x

24 G.M. Sheldrick, SHELXS 93, Univ. of Gottingen, 1993.

¨

Acknowledgements

x

Ž

.

25 P. McArdle, J. Appl. Crystallogr. 27 1994 438.

We thank the EPSRC for support and studentships

C.J.B. and C.B. .

Ž

.

Article Doi

The synthesis, structure and reactivity of aldehyde substituted η3-allylic complexes of molybdenum

DOI: 10.1016/S0022-328X(97)00542-1

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Article abstract of DOI:10.1016/S0022-328X(97)00542-1

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