Regioisomeric preferences in the orthomanganation of meta-substituted acetophenones and isopropyl benzoates, and application of iodo-demanganation with iodine chloride to the synthesis of 2-iodo-3-O-substituted and other ortho-iodo arylcarbonyl compounds

Article abstract of DOI:10.1016/S0022-328X(01)01174-3

Synthesis is reported of regioisomeric ortho-[Mn(CO)₄] derivatives of aryl ketones (2-chlorothioxanthen-9-one and 3′,4′-methylenedioxyacetophenone) and esters (isopropyl 3-methoxy- and 3-acetoxy-benzoate), as well as of the single ortho-[Mn(CO)

Full text of DOI:10.1016/S0022-328X(01)01174-3

Journal of Organometallic Chemistry 634 (2001) 157–166
www.elsevier.com/locate/jorganchem
Regioisomeric preferences in the orthomanganation of
meta-substituted acetophenones and isopropyl benzoates, and
application of iodo-demanganation with iodine chloride to the
synthesis of 2-iodo-3-O-substituted and other ortho-iodo
arylcarbonyl compounds
Janine M. Cooney, Louis H.P. Gommans, Lyndsay Main *, Brian K. Nicholson
Chemistry Department, School of Science and Technology, Uni6ersity of Waikato, Pri6ate Bag 3105, Hamilton, New Zealand
Received 21 May 2001; accepted 28 July 2001
Abstract
Synthesis is reported of regioisomeric ortho-[Mn(CO)4] derivatives of aryl ketones (2-chlorothioxanthen-9-one and 3%,4%-
methylenedioxyacetophenone) and esters (isopropyl 3-methoxy- and 3-acetoxy-benzoate), as well as of the single ortho-[Mn(CO)4]
products from methyl 4-methoxy- and 3,5-dimethoxy-benzoate. Factors influencing the preference for manganation at the
crowded positions ortho to the CꢀO in meta-substituted aryl ketones and esters are considered. The frequency of the lowest energy
metal carbonyl stretching mode is useful in the structural assignment of the regioisomers. Isopropyl 2-iodo-3-methoxy- and
2-iodo-3-acetoxy-benzoates are obtained by reaction of iodine chloride to replace the Mn(CO)4 group at the crowded 2-position
of the corresponding orthomanganated 3-O-substituted benzoate esters. ortho-Iodoacetophenones were prepared likewise, without
a-iodination, some with iodine in crowded positions (2%-iodo-3%-methoxy-, -3%,4%-methylenedioxy- and -3%,4%,5%-trimethoxy-acetophe-
none), others with O-protected 2%-hydroxy groups (2%-benzyloxy- and 2%-t-butyldimethylsilyloxy-3%,4%-dimethoxy-6%-iodobenzene
and 2%-t-butyldimethylsiloxy-6%-iodobenzene). Potential general synthetic routes to derivatives of 2-iodo-3-hydroxy-, 2-iodo-3,4-di-
hydroxy-, and 2-iodo-6-hydroxy-aryl carbonyl compounds are indicated. The corresponding routes to 3-iodo-4-acetyl-2,5-
dimethylthiophene and 3-iodo-2-acetylthiophene are also reported. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Manganese; Cyclometallation; Metallacycle; Iodination; o-Iodoacetophenones; o-Iodobenzoic acid esters
straints are not overriding in the 3%-substituted
acetophenone series [1b,3]: with 3%-OMe (1a) [1b,3], 3%-F
(1b) [3] and 3%-Cl (1c) [3], manganation occurs at the
sterically crowded 2%-position to form isomer 2, in
preference to reaction at the 6%-position to form 3. The
product preference is reversed, but only a little, with
bulky 3%-Br (1d) [3]. In contrast, for 3%-Me (1e), or-
thomanganation occurs almost exclusively at 6%-C [1b,3]
and for 3%-CF3 (1f) no substitution is detected in the
crowded 2%-position [3], although the net yield (of the
other isomer) is very low (11%) in this case. The
preference for the sterically crowded site in the 3%-OMe
case (1a) was suggested in the unpublished work [2]
possibly to arise from the coordination of a lone pair
on OMe in stabilising a complex such as that proposed
in 4 with Mn held close to C-2 immediately prior to its
1. Introduction and outline of current study
As first reported by Kaesz’ group [1,2], aryl ketones
can be cyclomanganated in the ortho position (‘or-
thomanganation’) with the tetracarbonylmanganese
[Mn(CO)4] group by reaction with methylpentacar-
bonylmanganese [1] or benzylpentacarbonylmanganese
[2] (e.g. Scheme 1). The reactions are envisaged as
involving prior coordination of RMn(CO)4 to the ke-
tone carbonyl, which delivers the substituting group to
the adjacent ring position with release of RH. In-
tramolecular delivery may explain why steric con-
* Corresponding author. Tel.: +64-7-8384385; fax: +64-7-
8384219.
E-mail address: l.main@waikato.ac.nz (L. Main).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01174-3

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J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
release as a 16-electron ArꢁMn(CO)3(R) species for
oxidative addition at C-2. Reversal of the product ratio
in the case of 3%,4%-dimethoxyacetophenone (1g) [4]
would be consistent with inability of the 3%-OMe to
effectively present a lone pair to the metal because the
Me group on 3%-O would be rotated towards the metal
coordination site so as to reduce the steric interaction
with the 4%-OMe, as indicated in structure 5; equally of
course steric hindrance at the 2%-position would thereby
be increased, though this is not an overriding limitation
to reaction as the ease of orthomanganation of 3%,4%,5%-
trimethoxyacetophenone [4,5] indicates. A steric com-
ponent must nevertheless be invoked if the donor
theory is to be extended to explain why the halo groups
promote 2%-substitution, because fluorine, the poorest
donor but smallest halogen, is the best ortho-directing
group (1b vs. 1c and 1d). This suggests a reasonable
alternative to the donor theory, which is that the 2%-po-
sition is activated to manganation by inductively elec-
tron-withdrawing groups in the 3%-position, with
overlaying steric effects playing a role.
We now report on orthomanganation in the crowded
position of other aryl carbonyl compounds including
3%,4%-methylenedioxyacetophenone (1h; Scheme 1) and
meta-substituted isopropyl benzoates (Scheme 2). Also
reported is orthomanganation of methyl 4-methoxyben-
zoate and methyl 3,5-dimethoxybenzoate.
The ease of subsequent replacement of Mn(CO)4 by
iodine using iodine chloride as first reported by us for
orthomanganated 3%,4%,5%-trimethoxyacetophenone [5] is
applied here, with particular interest in iodination at
the manganated 2-position in 3-O-substituted benzoate
esters (7) because this gives otherwise elusive crowded
iodo compounds (9; Scheme 3) with applications in
drugs synthesis (see Section 2). Also reported are the
ICl reactions of the new orthomanganated ketone 2h
and of some other orthomanganated ketones we have
previously synthesised [4] (refer to structures 15a–20a
in Section 2). They include examples chosen to check
the success of routes to ortho-iodination products
(16b–18b) of O-benzyl- and O-silyl-protected 2%-hy-
droxyacetophenones in the face of the restriction that
orthomanganation of 2%-hydroxyacetophenones with a
free OH group is unsuccessful [10], and, in the het-
eroaromatic area, of the acetylthiophene derivatives 19a
and 20a.
Scheme 1.
Scheme 2.
Scheme 3.
2. Results and discussion
2.1. Orthomanganation reactions
2.1.1. Ketones
Yields and isomer ratios for orthomanganation with
PhCH2Mn(CO)5 were similar to those reported else-
where in the cases of 3%-methoxyacetophenone [1b] and
of 3%-chloroacetophenone [3] (Scheme 1). For compari-
son with the 3%-Cl case, we tested 2-chlorothioxanthen-
9-one (10a; Scheme 4) in which the choice is between
sites in different rings, and found the reaction to
slightly favour the unsubstituted ring (C-8 over
crowded C-1) but the ratio (10b–10c) was close to 1:1
as in the 3%-chloroacetophenone case.
For comparison with the 3%-methoxy (1a) and 3%,4%-
dimethoxy (1g) cases, we studied 3%,4%-methylenedioxy-
acetophenone (1h) in which the donor lone pair on 3%-O

J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
159
2.2. Infrared spectra including structural assignment of
orthomanganation regioisomers
If assistance in manganation at the 2-position is
provided by the acetate carbonyl (13), the metal is
nevertheless coordinated in the final product by only
the benzoate ester CꢀO, as shown by the large shift (122
cm−1) in its wCꢀO relative to parent non-metalated ester
and by the minor effect on the acetate carbonyl (9
cm−1 shift in wCꢀO). Similar large metal-induced shifts
in wCꢀO of all the coordinating ketone and ester groups
in the cyclometalated ring are observed for all the other
complexes, as has previously been discussed [1b,6].
However, more subtle diagnostic data lie in the metal
carbonyl stretching frequencies. As typical of previously
reported cis-L2Mn(CO)4 complexes [1b,6], three metal
carbonyl bands are observed. Four bands are predicted
for cis-L2M(CO)4 with local C26 symmetry but for
orthomanganated derivatives the middle two bands are
commonly accidentally degenerate [1b], though there
are occasional exceptions, as in the manganated isopro-
pyl esters 7a and 7b studied here. It is the lowest
frequency band in the range 1940–60 cm−1 which has
empirical diagnostic value. It is consistently noted that
the crowded isomer formed by manganation at the
acetophenone 2%-position has a lowest frequency wCꢀO
value which is higher than that in the isomer man-
ganated in the remote 6%-position. The magnitude of the
shift is similar (10–16 cm−1) across the range of halo-
gens (2b–d vs. 3b–d) and the oxygen substituents OMe
(2a vs. 3a, 2g vs. 3g) and ꢁOCH2Oꢁ (2h vs. 3h); it
applies also to the esters 7a versus 8a. The one excep-
tion is with the acetoxy group in the isopropyl 3-ace-
toxybenzoate case where the shift is only 4 cm−1 (7b vs.
8b). The shift is consistent enough to suggest that it
may be used diagnostically as a guide to structural
assignment in other cases, i.e. the isomer with the
lowest wCꢀO is likely to be the uncrowded (6%-man-
ganated) isomer. Such generality is supported by a
similar shift (12 cm−1) with the manganated 2-
chlorothioxanthen-9-one isomers (10c vs. 10b) when the
metal is in alternative rings adjacent to, or remote from,
Cl. Related to this case and that for 3%,4%-dimethoxyace-
tophenone is the result for 2,4,5-triethoxybenzophenone
which was found to give ca. 30% substitution at the
6-position adjacent to the 4,5-diethoxy grouping and
ca. 60% at the 2%-position in the unsubstituted ring [7].
In this case, a shift of 8 cm−1 was observed, but
because the products could not be separated, the direc-
tion of the shift is not definite. It should be noted that
the shift as a guide to regioisomer structure applies only
where the substituent is electronegative halogen or oxy-
gen; the small shift in the case of the isomeric man-
ganated 3%-methylacetophenones (2e, prepared using
MeMn(CO)5 [1b], and 3e), is in the reverse direction.
Scheme 4.
is locked into an orientation appropriate for the pro-
posed [2] metal coordination (indicated in intermediate
11; cf. 4) at the now sterically less crowded 2%-position:
the ca. 20:1 preference for substitution in the 2%-position
now is much more dominant than for the 3%-OMe (1a)
case itself. This reveals some consistency in the trend in
ratio across the series 3%,4%-methylenedioxy (20:1), 3%-
methoxy (2:1) and 3%,4%-dimethoxy (1:3), irrespective of
whether it is a donor effect or an inductive effect of the
3%-substituent, modified by steric influence, which is
primarily responsible for the directive effect.
2.1.2. Esters
An early unpublished report [2] showed that, whereas
orthomanganation of methyl benzoate is very ineffi-
cient, with isopropyl benzoate an 85% yield is obtained.
Therefore, although we did find as reported here that
two methyl esters, methyl 4-methoxybenzoate and
methyl 3,5-dimethoxybenzoate, gave good yields (74
and 87%, respectively) of their orthomanganation prod-
ucts 12a and 12b, isopropyl esters were used in the
present 3-substituted benzoate study with the intention
of maximising yields prior to iodination (see below).
Isopropyl 3-methoxybenzoate (6a) undergoes manga-
nation with PhCH2Mn(CO)5 (Scheme 2) in 53% yield at
the 2-position to form 7a and 39% at the 6-position to
form 8a, the ratio being similar to that for 3%-methoxy-
acetophenone (1a). The effect of reduced donor ability
of the 3-O atom was tested with the reaction of isopro-
pyl 3-acetoxybenzoate (6b) in which the aryl-O in
OꢁCOCH3 will be a weaker donor than that in OꢁCH3
because of the electron-withdrawing effect of the acetyl
group. However, with a similar overall yield (89%), an
even stronger preference (8:1) for manganation in the
site adjacent to the substituent group (7b) showed that
lone pair donor ability of the oxygen atom bonded to
the 3-position is not paramount in determining the
reactivity. On first sight, this would seem to support the
alternative theory, that the directive effect of the 3-sub-
stituent is an inductive one, because OꢁCOCH3 will be
a better −I group with respect to C-2 than OꢁCH3. It
is possible, however, that the 3-OCOCH3 group coordi-
nates with Mn via the carbonyl oxygen thereby promot-
ing a more favourable arrangement [six-membered ring
in the proposed intermediate (13) vs. the apparently less
favourable four-membered (cf. 4)] for it to attack at
C-2. Any such coordination is not, however, retained in
the product (see Section 2.2).

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J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
2.3. NMR spectra
demanganation at the manganated carbon; it is possible
that this happens to some extent before the complete
reaction, i.e. some of the wayward iodination may
occur at the 5%- or 6%-site subsequent to demetalation.
From the final product ratio, the manganated carbon is
at least five times the more reactive with ICl, but a
better fix on the relative reactivities (and possibly a
better yield of 2%-iodinated product) might in future be
obtained by carrying out the reaction in the presence of
a trap for HCl, e.g. propylene oxide. In the case of the
ketones, another possible proton-releasing reaction is
iodination at the reactive a-carbon of the COCH3
group. However, there was no sign of a-iodo contami-
nant here, nor in the 2%-iodo-3%,4%,5%-trimethoxyace-
Structural assignments based on chemical shifts and
coupling constants are well established for proton and
carbon NMR spectra [1b,6], allowing for unambiguous
structural assignment of isomers in the present study
(see Section 3).
13C-NMR metal carbonyl signals are broadened,
probably because of coupling with 17O and 55Mn
quadrupoles [8], allowing them to be easily distin-
guished from the coordinated ketone carbonyl. The
signal at lowest field (ca. 220 ppm) is consistently to
lower field in the uncrowded isomer but by only a bare
1–2 ppm, so this shift is likely to be much less reliable
in structural diagnosis than the carbonyl frequency shift
in the infrared.
tophenone
formed
from
orthomanganated
3%,4%,5%-trimethoxyacetophenone (15a) as described in
Section 2.4.3. This contrasts with the occurrence of
some a-bromination in the corresponding reaction with
Br2 [6,10].
2.4. Synthesis of 3-substituted-2-iodoarylcarbonyl
compounds
Iodination to replace manganese (iodo-demangana-
tion) at the sterically crowded manganation sites in the
ketone complexes (2a, 2h) and the ester complexes (7a,
7b) was tested using the electrophilic reagent iodine
chloride in carbon tetrachloride [5] to see how well it
competed with iodo-deprotonation at other uncrowded
positions available, especially those activated to elec-
trophilic substitution. Reactions were quite slow at
room temperature and some were incomplete on
workup (see Section 3) so increasing the reaction time
and/or the reagent concentrations employed in this
initial standard survey should allow improved yields in
their cases. The important finding from this initial
study was that in almost all cases iodine was substituted
specifically into the manganated positions, even if
strongly sterically crowded, and this strongly enhances
the value of this synthetic route.
2.4.2. Orthomanganated esters with ICl
2.4.1. Orthomanganated 3-substituted acetophenones
with ICl
For the 3%-methoxyacetophenone case (2a), an excel-
lent 89% yield of the product iodinated in the crowded
manganated position (14a) is obtained.
Of particular synthetic value in the present study is
the highly specific route to 2-iodo-3-hydroxybenzoate
derivatives, as represented by 9a and 9b. Under the
non-optimised conditions used in this exploratory
study, 9a was obtained in 74% yield with recovery of
18% unreacted 7a, and 9b in a yield of 49% with
recovery of 35% unreacted 7b. Clearly the yields should
be improved with longer reaction times and/or higher
reactant concentrations. Such iodo compounds have
been important as precursors of many bioactive com-
pounds obtained via aryl–aryl coupling reactions at the
crowded iodo-substituted carbon, e.g. a synthesis of the
antibiotic gilvocarcin [11] incorporated a multi-step
synthesis of 2-iodo-3-methoxy-5-methylbenzyl alcohol
[12], followed by oxidation to 2-iodo-3-methoxy-5-
methylbenzoic acid. Esterification with a C-glycosidic-
a-naphthol allowed for the key intramolecular
Pd(II)-promoted coupling of the naphthyl b-carbon to
The one exception to specificity in iodination site was
found in the case of the 2%-manganated 3%,4%-methylene-
dioxyacetophenone (2h) which gave 2%-iodo-3%,4%-
methylenedioxyacetophenone (14b; 63%) but also a
small amount (12%) of product of iodination at either
the 5%- or the 6%-position, with replacement of Mn(CO)4
at the 2%-position by H. Application of standard sub-
stituent increments [9] on proton or carbon signals was
indecisive in assignment between the 5%- and 6%-isomers.
The presence of two activating oxygen substituents in
the aromatic ring would increase the reactivity with
electrophiles at the unsubstituted 5%- and 6%-positions,
and the HCl produced may be responsible for protio-

J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
161
the iodinated aryl carbon. A similar coupling strategy
exists in the Jourdan–Ullmann condensation of 3-sub-
stituted-2-iodobenzoic acids with 2-aminophenylacetic
acids to form analogues of the colon tumour active
agent xanthenone-4-acetic acid [13]. When electrophilic
nitration at the crowded 2-position of 3-hydroxyben-
zoic acids competes well with substitution in the much
less crowded but similarly activated 4- and 6-positions,
reaction with HNO3 may provide a relatively straight-
forward entry to 2-iodo compounds via amino and
diazonium intermediates, but the manganation route
may be preferred for its mild reaction conditions and
when directive effects of other ring substituents are
likely to influence the orientation of nitration. In this
context, it should be noted that the orthomanganated
complexes are air-stable compounds which can be chro-
matographed and handled without any special
precaution.
compounds should be applicable to the synthesis of
many types of compounds not accessible by direct
iodination as indicated in 21, including the 3-OH case
by removal of acetyl or other protective group. Like-
wise acetal- or ketal-protected 3,4-dihydroxy systems
analogous to the methylenedioxy compound 2h should
allow entry by removal of the protective group to
3,4-di-OH and otherwise di-O-substituted compounds
as indicated by 22 in both the ketone and ester series
(the latter convertible to carboxylic acid by hydrolysis),
with the proviso that iodination may also lead to some
5%- or 6%-iodo isomer as observed with 2h. 6%-Iodo-2%-hy-
droxyacetophenone derivatives and the corresponding
6-iodo-2-hydroxybenzoates (23) should also be gener-
ally accessible by these routes, subject to limitations
with the specificity of iodination when there are addi-
tional ring substituents.
2.4.3. Synthesis of other ortho-iodo aryl methyl ketones
A selection of aryl methyl ketones iodinated at posi-
tions not generally accessible by direct electrophilic
substitution, which would generally favour the position
meta to the ketone group, have been synthesised (15b–
20b). The reactions were carried out under standardised
conditions in this initial survey and yields have not
been optimised. The reactions are slow (days at room
temperature; see Section 3) but this is more than com-
pensated for by the specificity of the site of iodination.
There is some potential in the manganation route to
3. Experimental
3.1. General
ortho-iodination
of
2%-O-protected-acetophenones
(16a–18a) to provide a source of new 6%-iodinated-2%-
hydroxyacetophenones after removal of the protective
group. The thiophene derivatives 19b and 20b may have
applications in aryl coupling reactions in the heteroaro-
matic area.
Infrared spectra were recorded in hexane in a Digilab
FTS-45 instrument and mass spectra in a Varian MAT
CH5 spectrometer. NMR spectra in CDCl3 with Me4Si
internal standard were recorded in a Bruker AC-300;
for a few compounds spectral assignments could not be
unambiguously assigned to all signals and in these cases
the symbols * or c are used to denote pairs of
alternative assignments. Elemental analyses were car-
ried out at the University of Otago Microanalytical
Laboratory. Preparative chromatography was carried
out on 1 mm layers of silica (Merck Kieselgel 60PF254+
366).
Benzylpentacarbonylmanganese was prepared from
Mn2(CO)10 by the standard method [14]. Syntheses of
orthomanganated complexes other than those below
has been previously described [4]. New complexes were
prepared using PhCH2Mn(CO)5 and organic substrates
under reflux in heptane under nitrogen, normally over
2–3 h, followed by chromatographic purification as
described in the illustrative example for 10 below. Or-
ganic reagents were sourced from Aldrich with the
exception of the benzoate esters which were prepared
without yield optimisation from 3-hydroxybenzoic acid
as follows.
2.5. Summary: potential synthetic applications of the
manganation–iodination sequence
Based on the current results, the manganation–iodi-
nation route to 3-substituted-2-iodophenylcarbonyl

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J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
3
3.2. Synthesis of esters
Hz, H-2), 7.43 (1H, t, J5,6=3J5,4=7.9 Hz, H-5), 7.26
3
4
4
(1H, ddd, J4,5=7.9 Hz, J4,2=2.5 Hz, J4,6=1.2 Hz,
H-4), 5.24 (1H, m, 3J=6.3 Hz, 1-COOCH(CH3)2), 2.31
(3H, s, 3-OCOCH3), 1.35 (6H, d, 3J=6.3 Hz, 1-
COOCH(CH3)2). 13C-NMR: l 169.3 (s, 3-OCOCH3),
165.1 (s, 1-COOCH(CH3)2), 150.6 (s, C-3), 132.5 (s,
C-1), 129.3 (d, C-5), 127.0 (d, C-6), 126.1 (d, C-4), 122.8
(d, C-2), 68.8 (d, 1-COOCH(CH3)2), 21.9 (q, 1-
COOCH(CH3)2), 21.1 (q, 3-OCOCH3).
3.2.1. Isopropyl 3-hydroxybenzoate
3-Hydroxybenzoic acid (30 g, 0.217 mol), isopropyl
alcohol (170 ml, 2.17 mol) and conc. H2SO4 (2.7 ml)
were heated under reflux for 18.5 h. After removal of
excess alcohol the residue was added to water (100 ml)
and extracted with Et2O (40 ml, 2×10 ml). The Et2O
solution was washed with saturated NaHCO3 solution,
then water and dried over MgSO4. Solvent removal and
recrystallisation from hot EtOH gave isopropyl 3-hy-
droxybenzoate as white chunky crystals, m.p. 55.5–
57 °C. 1H-NMR: l 7.61 (1H, dt, 3J6,5=7.9 Hz,
3.3. Orthomanganation reactions
3.3.1. Standard method for orthomanganation
4J6,4=4J6,2=1.3 Hz, H-6), 7.55 (1H, dd, J2,4=2.7 Hz,
4
2-Chlorothioxanthene-9-one (10a, 0.126 g, 0.511
mmol) and PhCH2Mn(CO)5 (0.175 g, 0.613 mmol) were
dissolved in heptane (AR, 25 ml) and the solution
degassed and flushed with nitrogen several times. After
refluxing under nitrogen for 90 min, the heptane was
removed under vacuum. The resultant orange solid was
dissolved in CH2Cl2 and chromatographed on silica
plates with 1:10 v/v Et2O–petroleum spirit; b.p. 60–
80 °C as the eluent. A broad bright orange band was
extracted to give h2-(7-chlorothioxanthen-9-on-1-
yl)tetracarbonylmanganese (10b) (0.108 g, 51%) which
was crystallised from petroleum spirit as orange feath-
ers, m.p. 143.5–145 °C. Anal. Found: C, 49.29; H,
1.62. Calc. for C17H6O5ClMnS: C, 49.48; H, 1.47%. IR:
3
4J2,6=1.3 Hz, H-2), 7.30 (1H, t, J5,4=3J5,6=7.9 Hz,
H-5), 7.04 (1H, ddd, 3J4,5=7.9 Hz, 4J4,2=2.7 Hz,
4J4,6=1.3 Hz, H-4), 5.39 (1H, s, br, 3-OH), 5.24 (1H,
m, 3J=6.2 Hz, 1-COOCH(CH3)2), 1.36 (6H, d, 3J=6.2
Hz, 1-COOCH(CH3)2). 13C-NMR: l 166.9 (s, 1-
COOCH(CH3)2), 156.2 (s, C-3), 131.9 (s, C-1), 129.7 (d,
C-5), 121.7 (d, C-6), 120.4 (d, C-4), 116.5 (d, C-2), 69.2
(d, 1-COOCH(CH3)2), 21.9 (q, 1-COOCH(CH3)2).
3.2.2. Isopropyl 3-methoxybenzoate
Isopropyl 3-hydroxybenzoate (4 g, 0.022 mol),
K2CO3 (6.06 g, 0.044 mol) and MeI (2.75 ml, 0.044
mol) were heated under reflux in acetone (AR, 100 ml)
overnight. The solution was filtered and after removal
of solvent the residue was added to water (100 ml) and
extracted with Et2O (1×40 ml, 2×20 ml). The Et2O
solution was washed successively with NaOH (2
mol l−1) and water, and dried over MgSO4. Solvent
removal gave isopropyl 3-methoxybenzoate as a colour-
1
w(CO) 2083 (m), 1997 (vs, br), 1946 (s). H-NMR: l
4
5
8.52 (1H, dd, J8,6=2.1 Hz, J8,5=0.9 Hz, H-8), 8.14
3
4
(1H, dd, J2,3=7.1 Hz, J2,4=1.0 Hz, H-2), 7.64–7.63
3
3
(2H, m, H-5,6), 7.51 (1H, dd, J3,4=8.0 Hz, J3,2=7.1
Hz, H-3), 7.39 (1H, dd, 3J4,3=8.0 Hz, 3J4,2=1 Hz,
H-4). 13C-NMR: l 221.0 (s, br, CO), 213.2 (s, br, CO),
211.2 (s, 2×CO), 194.3 (s, C-9), 193.5 (s, C-1), 139.9 (s,
C-4a), 139.0 (d, C-2), 138.2 (s, C-10a), 137.1 (s, C-9a),
133.4 (d, C-6), 132.8 (s, C-7), 132.5 (d, C-3), 128.9 (s,
C-8a), 128.9 (d, C-8), 127.5 (d, C-5), 120.2 (d, C-4). A
second band yielded h2-(1-(2-chlorothioxanthen-9-on-1-
yl)tetracarbonylmanganese [(10c); 82 mg, 39%) which
crystallised from petroleum spirit as yellow needles,
m.p. 136 °C (dec.). Anal. Found: C, 49.51; H, 1.26.
Calc. for C17H6O5ClMnS: C, 49.48; H, 1.47%. IR:
1
1
less liquid (3.20 g, 75%), pure by H-NMR. H-NMR:
l 7.62 (1H, dt, 3J6,5=8.0 Hz, 4J6,4=4J6,2=1.2 Hz,
4
4
H-6), 7.55 (1H, dd, J2,4=2.7 Hz, J2,6=1.2 Hz, H-2),
3
7.32 (1H, t, J5,6=3J5,4=8.0 Hz, H-5), 7.07 (1H, ddd,
4
4
3J4,5=8:0 Hz, J4,2=2.7 Hz, J4,6=1.2 Hz, H-4), 5.24
3
(1H, m, J=6.2 Hz, 1-COOCH(CH3)2), 3.83 (3H, s,
3
3-OCH3), 1.36 (6H, d, J=6.2 Hz, 1-COOCH(CH3)2).
13C-NMR: l 165.9 (s, 1-COOCH(CH3)2), 159.6 (s, C-
3), 132.3 (s, C-1), 129.3 (d, C-5), 121.9 (d, C-6), 119.0
(d, C-4), 114.1 (d, C-2), 68.4 (d, 1-COOCH(CH3)2),
55.3 (q, 3-OCH3), 21.9 (q, 1-COOCH(CH3)2).
1
w(CO) 2085 (m), 1999 (vs, br), 1958 (s). H-NMR: l
3
4
8.53 (1H, dt, J8,7=8.2 Hz, J8,6=5J8,5=0.9 Hz, H-8),
3
7.72–7.69 (2H, m, H-5,6), 7.61 (1H, d, J3,4=8.4 Hz,
H-3), 7.56–7.51 (1H, m, H-7), 7.35 (1H, d, J4,3=8.4
3
Hz, H-4). 13C-NMR: l 219.6 (s, br, CO), 214.8 (s, br,
CO), 210.6 (s, 2×CO), 194.7 (s, C-9), 189.3 (s, C-1),
146.2 (s, C-2), 139.4 (s, C-10a), 138.1 (s, C-9a), 137.9 (s,
C-4a), 133.4 (d, C-6), 133.3 (d, C-3), 129.8 (d, C-8),
127.8 (s, C-8a), 126.7 (d, C-7), 126.0 (d, C-5), 122.4 (d,
C-4).
3.2.3. Isopropyl 3-acetoxybenzoate
Isopropyl 3-hydroxybenzoate (4.16 g, 0.023 mol) and
Ac2O (3.27 ml, 0.035 mol) were stirred overnight in Py
(10 ml). The residue was poured into water (100 ml)
and extracted with Et2O (40 ml, 2×20 ml). The com-
bined Et2O extract was washed with HCl (2 mol l−1),
NaOH (2 mol l−1), then water, and dried over MgSO4.
Ether removal gave isopropyl 3-acetoxybenzoate as a
very pale yellow liquid (4.05 g, 79%), pure by 1H-NMR.
The following orthomanganated complexes were sim-
ilarly prepared and purified.
From 3%-chloroacetophenone (1c; 179 mg, 1.158
mmol) and PhCH2Mn(CO)5 (397 mg, 1.389 mmol)
under reflux overnight were obtained:
3
4
1H-NMR: l 7.91 (1H, dt, J6,5=7.9 Hz, J6,4=4J6,2
=
4
4
1.2 Hz, H-6), 7.73 (1H, dd, J2,4=2.5 Hz, J2,6=1.2

J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
163
(i)
h2-(2-Acetyl-6-chlorophenyl)tetracarbonylman-
(s, br, CO), 211.9 (s, br, 2×CO), 179.9 (s, C-1), 170.9
(s, 6-COOCH(CH3)2), 167.6 (s, C-2), 136.4 (s, C-6),
125.5 (d, C-4), 121.7 (d, C-5), 113.8 (d, C-3), 72.1 (d,
6-COOCH(CH3)2), 55.5 (q, 2-OCH3), 21.8 (q, 6-
COOCH(CH3)2). (ii) h2-(4-Methoxy-2-isopropoxycar-
bonylphenyl)tetracarbonylmanganese [(8a); 229 mg,
39%] a yellow oil which failed to crystallise. IR: w(CO)
2083 (m), 1994 (vs), 1991 (s), 1944 (s). 1H-NMR: l
ganese [(2c); 156 mg, 42%] which crystallised from
hexane–Et2O as small yellow–orange regular crystals,
m.p. 106–107.5 °C (lit. 105–107 °C [3]). IR: w(CO)
1
2088 (m), 1998 (vs, br), 1961 (s). H-NMR: l 7.73 (1H,
d, 3J3,4=7.6 Hz, H-3), 7.53 (1H, d, 3J5,4=7.6 Hz, H-5),
7.12 (1H, t, 3J4,3=3J4,5=7.6 Hz, H-4), 2.60 (3H, s,
2-COCH3). 13C-NMR: l 219.7 (s, br, CO), 217.2 (s,
2-COCH3), 210.8 (s, br, 2×CO), 189.9 (s, C-1), 149.5
(s, C-6), 146.4 (s, C-2), 134.6 (d, C-5), 129.5 (d,C-3),
125.8 (d, C-4), 25.1 (q, 2-COCH3); one metal carbonyl
signal not observed. (ii) h2-(2-acetyl-4-chlorophenyl)-
tetracarbonylmanganese [(3c); 137 mg, 37%] which
crystallised from hexane–Et2O as small yellow–orange
regular crystals, m.p. 131–133 °C (lit. 132–134 °C [3].
3
4
67.82 (1H, d, J6,5=8.1 Hz, H-6), 7.28 (1H, d, J3,5
=
3
4
2.6 Hz, H-3), 7.15 (1H, dd, J5,6=8.1 Hz, J5,3=2.6
3
Hz, H-5), 5.23 (1H, m, J=6.2 Hz, 2-COOCH(CH3)2),
3.83 (3H, s, 4-OCH3), 1.35 (6H, d, 3J=6.2 Hz, 2-
COOCH(CH3)2). 13C-NMR: l 221.5 (s, br, CO), 213.0
(s, br, CO), 212.1 (s, br, 2×CO), 179.6 (s, C-1), 171.5
(s, 2-COOCH(CH3)2), 157.5 (s, C-4), 141.2 (d, C-6),
135.2 (s, C-2), 122.6 (d, C-5), 113.1 (d, C-3), 72.3 (d,
2-COOCH(CH3)2), 55.4 (q, 4-OCH3), 21.8 (q, 2-
COOCH(CH3)2).
1
IR: w(CO) 2085 (m), 1997 (vs, br), 1949 (s). H-NMR:
l 88.02 (1H, d, 3J6,5=7.9 Hz, H-6), 7.81 (1H, d,
4J3,5=2.1 Hz, H-3), 7.39 (1H, dd, 3J5,6=7.9 Hz,
4J5,3=2.1 Hz, H-5), 2.61 (3H, s, 2-COCH3). 13C-NMR:
l 221.0 (s, br, CO), 216.2 (s, 2-COCH3), 211.0 (s, br,
2×CO), 191.6 (s, C-1), 146.4 (s, C-2), 142.4 (d, C-6),
133.7 (d, C-5), 130.9 (d, C-3), 130.5 (s, C-4), 24.7 (q,
2-COCH3); one metal carbonyl signal not observed.
From 3%,4%-methylenedioxyacetophenone (1h, 145 mg,
0.883 mmol) and PhCH2Mn(CO)5 (303 mg, 1.060
mmol) under reflux over 2.5 h were obtained:
From isopropyl 3-acetoxybenzoate (6b; 385 mg, 1.73
mmol) and PhCH2Mn(CO)5 (595 mg, 2.08 mmol) under
reflux over 3 h were obtained:
(i) h2-(2-Acetoxy-6-isopropoxycarbonylphenyl)tetra-
carbonylmanganese [(7b); 533 mg, 79%] a yellow oil
which failed to crystallise. Anal. Found: C, 49.74; H,
3.53. Calc. for C16H13O8Mn: C, 49.50; H, 3.38%. IR:
1
w(CO) 2090 (m), 2006 (s), 1994 (s), 1948 (s). H-NMR:
(i) h2-(6-Acetyl-2,3-methylenedioxyphenyl)tetracar-
bonylmanganese [(2h); 251 mg, 86%] which crystallised
from hexane–Et2O as yellow feathers, m.p. 121–
122.5 °C. Anal. Found: C, 47.30; H, 2.19. Calc. for
C13H7O7Mn: C, 47.30; H, 2.14%. IR: w(CO) 2086 (m),
l 7.65 (1H, m, second order coupling, H-5), 7.21–7.15
(2H, m, second order coupling, H-3,4), 5.23 (1H, m,
3J=6.2 Hz, 6-COOCH(CH3)2), 2.30 (311, s, 2-
OCOCH3), 1.36 (6H, d, 3J=6.2 Hz, 6 COOCH(CH3)2).
13C-NMR: l 220.9 (s, br, CO), 213.5 (s, br, CO), 210.5
(s, br, 2×CO), 179.7 (s, C-1), 172.6 (s, 2-OCOCH3),
170.6 (s, 6-COOCH(CH3)2), 160.4 (s, C-2), 137.1 (s,
C-6), 127.5 (d, C-5), 127.0 (d, C-4), 125.5 (d, C-3), 72.7
(d, 6-COOCH(CH3)2), 21.8 (q, 6-COOCH(CH3)2), 21.1
(q, 2-OCOCH3). (ii) h2-(4-Acetoxy-2-isopropoxycar-
bonylphenyl)tetracarbonylmanganese [(8b); 69 mg,
10%], a yellow oil which failed to crystallise. IR: w(CO)
1
3
1997 (vs), 1960 (s). H-NMR: l 7.58 (1H, d, J5,4=8.0
Hz, H-5), 6.67 (1H, d, J4,5=8.0 Hz, H-4), 6.09 (2H, s,
3
2-OCH2O-3), 2.53 (3H, s, 6-COCH3). 13C-NMR: l
219.9 (s, br, CO), 213.4 (s, 6-COCH3), 211.0 (s, br,
2×CO), 163.1 (s, C-1), 157.9 (s, C-2), 149.8 (s, C-3),
141.2 (s, C-6), 129.4 (d, C-5), 105.4 (d, C-4), 100.7 (t,
2-OCH2O-3), 24.2 (q, 6-COCH3); one metal carbonyl
signal not observed. MS; m/z: 330 (6.7, [P+]), 274 (7.5,
[P+−56], [P+−2CO]), 246 (15.0, [P+−84], [P+−
3CO]), 218 (100, [P+−112], [P+−4CO]). (ii) h2-(2-
Acetyl-4,5-methylenedioxyphenyl)tetracarbonylman-
ganese [(3h); 11 mg, ꢀ4%) as a yellow oil. IR: w(CO)
2082 (m), 1997 (vs, br), 1944 (s).
1
2083 (m), 1995 (s, br), 1944 (s). H-NMR: l 7.93 (1H,
d, 3J6,5=8.0 Hz, H-6), 7.46 (1H, d, 4J3,5=2.4 Hz, H-3),
3
4
7.17 (1H, dd, J5,6=8.0 Hz, J5,3=2.4 Hz, H-5), 5.23
3
(1H, m, J=6.2 Hz, 2-COOCH(CH3)2), 2.31 (3H, s,
4-OCOCH3), 1.35 (6H, d, 3J=6.2 Hz, 2-
COOCH(CH3)2). 13C-NMR: l 221.2 (s, br, CO), 212.7
(s, br, CO), 211.5 (s, br, 2×CO), 180.2 (s, C-1), 179.3
(s, 4-OCOCH3), 169.7 (s, 2-COOCH(CH3)2), 148.1 (s,
C-4), 141.4 (d, C-6), 135.6 (s, C-2), 127.2 (d, C-5), 121.6
(d, C-3), 72.6 (d, 2-COOCH(CH3)2), 21.8 (q, 2-
COOCH(CH3)2), 21.2 (q, 4-OCOCH3).
From isopropyl 3-methoxybenzoate (6a; 319 mg, 1.64
mmol) and PhCH2Mn(CO)5 (564 mg, 1.97 mmol) under
reflux over 5 h were obtained:
(i) h2-(2-Methoxy-6-isopropoxycarbonylphenyl)tetra-
carbonylmanganese [(7a); 313 mg, 53%] which crys-
tallised from hexane–Et2O as yellow needles, m.p.
82.5–83.5 °C. IR: w(CO) 2083 (m), 1993 (vs), 1955 (s).
From methyl 4-methoxybenzoate (113 mg, 0.68
mmol)) and PhCH2Mn(CO)5 (233 mg, 0.82 mmol) un-
der reflux over 3 h was obtained h2-(5-methoxy-2-
methoxycarbonylphenyl)tetracarbonylmanganese (12a,
226 mg, 74%) which crystallised from hexane–Et2O as
yellow feathers, m.p. 105–107 °C. Anal. Found: C,
46.83; H, 2.69. Calc. for C13H907Mn: C, 47.01; H,
1H-NMR: l 7.38 (1H, d, J5,4=7.6 Hz, H-5), 7.12 (1H,
3
t, 3J4,3=3J4,5=7.6 Hz, H-4), 6.91 (1H, d, 3J3,4=7.6
3
Hz, H-3), 5.20 (1H, m, J=6.2 Hz, 6-COOCH(CH3)2),
3.85 (3H, s, 2-OCH3), 1.35 (6H, d, 3J=6.2 Hz, 6-
COOCH(CH3)2). 13C-NMR: l 220.6 (s, br, CO), 214.3

164
J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
141.0 (s, 1%-C), 107.8 (d, 6%-C), 79.8 (s, 2%-C), 60.93 (q,
OCH3).
2.73%. IR: w(CO) 2085 (m), 1996 (vs, br), 1944 (s).
3
1H-NMR: l 7.66 (1H, d, J3,4=88 Hz, H-3), 7.45 (1H,
h2-(2-Methoxy-6-isopropoxycarbonylphenyl)tetracar-
bonylmanganese (7a) was reacted similarly with ICl for
6 days to give 18% recovery of 7a and 74% isopropyl
2-iodo-3-methoxybenzoate (9a), a colourless oil. 1H-
d, 4J6,4=2.3 Hz, H-6), 6.63 (1H, dd, 3J4,3=8.8 Hz,
4J4,6=2.3 Hz, H-4), 3.93 (3H, s, 2-COOCH3*), 3.92
(3H, s, 5-OCH3*). 13C-NMR: l 221.4 (s, br, CO), 213.2
(s, br, CO), 212.0 (s, br, 2×CO), 187.8 (s, C-1), 179.9
(s, 2-COOCH3), 163.9 (s, C-5), 130.7 (d, C-3), 127.0 (s,
C-2), 124.2 (d, C-6), 111.4 (d, C-4), 55.3 (q, 5-OCH3),
53.9 (q, 2-COOCH3). MS; m/z: 332 (4.2, [P+]), 276
(4.2, [P+−2CO]), 248 (17.5, [P+−3CO]), 220 (100,
[P+−4CO]).
3
NMR: l 7.29 (1H, t, J5,4=3J5,6=7.9 Hz, H-5), 7.14
3
3
(1H, dd, J6,5=7.9 Hz, J6,4=1.3 Hz, H-6), 6.86 (1H,
3
4
dd, J4,5=7.9 Hz, J4,6=1.3 Hz, H-4), 5.25 (1H, m,
3J=6.3 Hz, 1-COOCH(CH3)2), 3.85 (3H, s, 3-OCH3),
1.37 (6H, d, J=6.3 Hz, 1-COOCH(CH3)2). 13C-NMR:
3
l 167.3 (s, 1-COOCH(CH3)2), 158.6 (s, C-3), 139.8 (s,
C-1), 129.3 (d, C-5), 122.0 (d, C-6), 112.7 (d, C-4), 86.2
(s, C-2), 69.7 (d, 1-COOCH(CH3)2), 56.8 (q, 3-OCH3),
21.9 (q, 1-COOCH(CH3)2). MS; m/z: 278 ([P+−
C(CH3)2]).
From methyl 3,5-dimethoxybenzoate (134 mg, 0.683
mmol) and PhCH2Mn(CO)5 (234 mg, 0.82 mmol) under
reflux over 2.75 h was obtained h2-(2,4-dimethoxy-6-
methoxycarbonylphenyl)tetracarbonylmanganese (12b,
247 mg, 87%) which crystallised from hexane–Et2O as
orange blocks, m.p. 108–109 °C. Anal. Found: C,
46.44; H, 2.87. Calc. for C14H11O8Mn: C, 46.43; H,
3.06%. IR: w(CO) 2084 (m), 1992 (vs, br), 1954 (s).
1H-NMR: l 6.92 (1H, d, 4J5,3=2.1 Hz, H-5*), 6.60
(1H, d, 4J3,5=2.1 Hz, H-3*), 3.95 (3H, s, 6-COOCH3c),
3.82 (3H, s, 2-OCH3c), 3.80 (3H, s, 4-OCH3c). 13C-
NMR: l 220.8 (s, br, CO), 214.3 (s, br, CO), 211.9 (s,
br, 2×CO), 180.4 (s, 6-COOCH3), 168.1 (s, C-2*),
161.1 (s, C-1*), 159.4 (s, C-4), 134.8 (s, C-6), 104.5 (d,
C-5c), 104.3 (d, C-3c), 55.5 (q, 2- and 4-OCH3), 54.2
(q, 6-COOCH3). MS; m/z: 362 (2.6, [P+]), 306 (1.9,
[P+−2CO]), 278 (13.3, [P+−3CO]), 250 (100, [P+−
4CO]).
h2-(2-Acetoxy-6-isopropoxycarbonylphenyl)tetracar-
bonylmanganese (7b) was reacted similarly with ICl for
3 days, giving 35% recovery of 7b and isopropyl 2-iodo-
3-acetoxy-2-iodobenzoate (9b; 49%), a colourless oil.
3
4
1H-NMR: l 7.53 (1H, dd, J6,5=7.9 Hz, J6,4=1.5 Hz,
H-6), 7.36 (1H, t, J5,4=3J5,6=7.9 Hz, H-5), 7.15 (H,
3
3
4
dd, J4,5=7.9 Hz, J4,6=1.5 Hz, H-4), 5.25 (1H, m,
3J=6.3 Hz, 1-COOCH(CH3)2), 2.36(H, s, 3-OCOCH3),
1.37 (6H, d, J=6.3 Hz, 1-COOCH(CH3)2). 13C-NMR:
3
l 168.5 (s, 3-OCOCH3), 166.1 (s, 1-COOCH(CH3)2),
152.1 (s, C-3), 138.9 (s, C-1), 129.1 (d, C-5), 127.8 (d,
C-6), 125.3 (d, C-4), 91.6 (d, C-2), 69.9 (d, 1-
COOCH(CH3)2), 21.9 (q, 1-COOCH(CH3)2), 21.3 (q,
3-OCOCH3). MS; m/z: 289 ([P+−OCH(CH3)2]).
h2-(6-Acetyl-2-methoxyphenyl)tetracarbonylmangan-
ese (2a) was reacted similarly with ICl for 5 days to give
2%-iodo-3%-methoxyacetophenone (14a; 0.103 g, 89%), a
colourless oil. Anal. Found: C, 39.63; H, 3.36; I, 46.05.
3.4. Iodo-demanganation reactions with ICl
The standard iodination method is described here for
the preparation of 2%-iodo-3%,4%,5%-trimethoxyacetophe-
none (15b) [5] and other preparations follow in numeri-
cal order of iodination product:
1
Calc. for C9H902I: C, 39.16; H, 3.29; I, 45.97%. H-
3
NMR: l 7.31 (1H, t, J5%,4%=3J5%,6%=8.0 Hz, H-5%), 6.88
3
4
(1H, dd, J6%,5%=8.0 Hz, J6%,4%=1.1 Hz, H-6%), 6.84 (1H,
h2 -(2-Acetyl-3,4,5-trimethoxyphenyl)tetracarbonyl-
manganese (15a; 0.151 g, 0.40 mmol) was dissolved in
nitrogen-saturated CCl4 (2 ml). A freshly prepared solu-
tion of ICl (0.065 g, 0.40 mmol) in nitrogen-saturated
CCl4 (2 ml) was added. The flask was stoppered and
left at room temperature for 4 days after which time the
colour of ICl had disappeared and an orange precipi-
tate was visible. The solid was removed by filtration: it
was identified by IR as mainly [IMn(CO)4]2 [15]. The
filtrate solvent was removed under vacuum, and the
residue chromatographed on a silica layer (3:7 Et2O–
light petroleum, b.p. 60–80 °C) to give 2%-iodo-3%,4%,5%-
trimethoxyacetophenone (15b; 0.125 g, 93%) as a
colourless oil. Recrystallisation from hexane gave white
needles, m.p. 54 °C. Anal. Found: C, 39.31; H, 3.90.
3
4
dd, J4%,5%=8.0 Hz, J6%,4%=1.1 Hz, H-4%), 3.87 (3H, s,
3%-OCH3), 2.56 (3H, s, H-2). 13C-NMR: l 203.4 (s,
C-1), 158.3 (s, C-3), 148.0 (s, C-1%), 129.8 (d, C-5%),
119.5 (d, C-6%), 112.1 (d, C-4%), 83.0 (s, C-2%), 56.8 (q,
3%-OCH3), 30.1 (q, C-2). MS; m/z: 276 [P+].
h2 - (6 - Acetyl - 2,3 - methylenedioxyphenyl)tetracar-
bonylmanganese (2h) was reacted similarly with ICl for
5 days, giving 12% recovery of 2h and a mixture
containing
2%-iodo-3%,4%-methylenedioxyacetophenone
1
(14b; 63% from 2h by H-NMR) and either the 5%- or
6%-iodo isomer of 3%,4%-methylenedioxyacetophenone
(12% from 2h). The major and expected isomer 2%-iodo-
3%,4%-methylenedioxyacetophenone (14b) was obtained
pure by fractional crystallisation from benzene–hep-
tane as white crystals, m.p. 114 °C. Anal. Found: C,
37.34; H, 2.77; I, 43.62. Calc. for C9H7O3I: C, 37.27; H,
1
Calc. for C11H13IO4: C, 39.35; H, 3.97%. H-NMR: l
1
3
6.75 (s, 1H, 6%-H), 3.86 (s, 3H, OCH3), 3.84 (s, 6H,
2×OCH3), 2.58 (s, 3H, COCH3). 13C-NMR: l 202.0 (s,
CO), 153.8 (s, 3%-C), 153.5 (s, 5%-C), 147.8 (s, 4%-C),
2.43; I, 43.75%. H-NMR: l 7.29 (1H, d, J6%,5%=8.1
3
Hz, H-6%), 6.77 (1H, d, J5%,6%=8.1 Hz, H-5%), 6.10 (2H,
s, 3%-OCH2O-4%), 2.59 (3H, s, COCH3). 13C-NMR: l

J.M. Cooney et al. / Journal of Organometallic Chemistry 634 (2001) 157–166
165
25.5 (q, [CH3]3C)), 18.0 (s, [CH3]3C), −4.36 (q,
[CH3]2Si).
198.0 (s, C-1), 151.1 (s, C-3%*), 148.3 (s, C-4%*), 134.7 (s,
C-1%), 125.6 (d, C-6%), 107.4 (d, C-5%), 101.0 (t, 3%-
OCH2O-4%), 69.9 (s, C-2%), 28.8 (q, C-2). MS; m/z: 290
[P+].
The other isomer could not be obtained pure from
the crystallisation residue. It had the following spectral
characteristics which did not allow distinction between
the 5%- and 6%-iodinated isomer of 3%,4%-(methylene-
dioxy)acetophenone: 1H-NMR: l 7.35 (1H, s), 7.04
(1H, s), 5.99 (2H, s, ꢁCH2ꢁ), 2.52 (3H, s, ꢁCOCH3).
13C-NMR: l 199.7 (s, ꢁCOCH3), 150.3 (s), 148.2 (s),
136.3 (s), 120.4 (d), 109.0 (d), 102.4 (t), 81.5 (s), 29.2 (q,
ꢁCOCH3).
h2 -(2,5-Dimethyl-4-acetylthien-3-yl)tetracarbonyl-
manganese (19a) was reacted similarly with ICl for 24 h
to give 3-acetyl-2,5-dimethyl-4-iodothiophene (19b) as a
white solid (100%). Recrystallisation from hexane gave
fine white needles, m.p. 45.5–46.5 °C. Anal. Found: C,
34.53; H, 3.11. Calc. for C8H9IOS: C, 34.30; H, 3.24%.
1H-NMR: l 2.62 (s, 3H, CH3PhP), 2.55 (s, 3H, CH3),
2.42 (s, 3H, CH3). 13C-NMR (CDCl3): l 198.2 (s, CO),
141.6 (s, 5-C), 140.3 (s, 2-C), 136.0 (s, 3-C*), 31.5 (q,
COCH3), 18.1 (q, 5-CH3), 15.2 (q, 2-CH3), (arylCꢁI
signal obscured under solvent signal). 13C-NMR
(CD3COCD3): l 198.0 (s, CO), 142.7 (s, 5-C), 140.2 (s,
2-C*), 136.6 (s, 3-C*), 79.3 (s, 4-C), 31.5 (q, COCH3),
18.1 (q, 5-CH3), 14.9 (q, 2-CH3); methyl ketone quartet
obscured beneath solvent signal.
h2-(2-Acetyl-3-benzyloxy-4,5-dimethoxyphenyl)tetra-
carbonylmanganese (16a) was reacted and worked up
similarly after 4 days even though the colour of ICl had
not fully disappeared. Bands of the preparative layer
silica plate were unreacted orthomanganated ketone
(30%) and 2%-benzyloxy-3%,4%-dimethoxy-6%-iodoace-
tophenone (16b; 63%), white crystals, m.p. 86.5–
87.5 °C. Anal. Found: C, 49.64; H, 4.33. Calc. for
h2 - (2 - Acetylthieny - 3 - yl)tetracarbonylmanganese
(20a) was reacted similarly with ICl for 24 h to give
2-acetyl-3-iodothiophene (20b) [16] as a pale yellow
solid (75%). Recrystallisation from hexane gave white
crystals, m.p. 59–60 °C. Anal. Found: C, 28.52; H,
1
C17H17IO4: C, 49.53; H, 4.16%. H-NMR: l (s, br, 5H,
1
2.02. Calc. for C6H5IOS: C, 28.59; H, 2.02%. H-NMR:
PhH), 7.09 (s, 1H, 5%-H), 5.03 (s, 2H, OCH2PhPhP),
3.86 (s, 6H, 2×OCH3), 2.43 (s, 3H, COCH3). 13C-
NMR: l 202.6 (s, CO), 154.4 (s, 4%-C), 149.0 (s, 2%-C),
142.4 (s, 3%-C), 136.5 (s, 1%-C), 128.2 (d, Ph), 128.0 (d,
Ph), 118.3 (d, 5%-C), 81.7 (s, 6%-C), 76.2 (t, OCH2Ph),
60.74 (q, OCH3), 56.19 (q, OCH3), 31.02 (q, COCH3).
h2-(2-Acetyl-3-t-butyldimethylsiloxy-4,5-
l 7.45 (d, J=4.8 Hz, 1H, 5-HPhP), 7.25 (d, J=4.8 Hz,
1H, 4-H), 2.67 (s, 3H, COCH3). 13C-NMR: l 189.6 (s,
CO), 140.3 (s, 2-C), 139.6 (d, 4-C), 132.9 (d, 5-C), 83.6
(s, 3-C), 29.5 (q, COCH3).
Acknowledgements
dimethoxyphenyl)tetracarbonylmanganese (17a) was re-
acted similarly with ICl to give 2%-t-butyldimethyl-
siloxy-3%,4%-dimethoxy-6%-iodoacetophenone (17b; 95%),
white crystals, m.p. 86.5–87.5 °C. Anal. Found: C,
44.11; H, 5.83. Calc. for C16H25IO4Si: C, 44.04; H,
5.83%. 1H-NMR: l 7.10 (s, 1H, 5%-H), 3.92 (s, 3H,
OCH3PhP), 3.86 (s, 3H, OCH3), 2.56 (s, 3H, COCH3),
0.97 (s, 9H, t-BuꢁH), 0.16 (s, 6H, Me2Si). 13C-NMR: l
203.1 (s, CO), 154.2 (s, 4%-C), 145.8 (s, 2%-C), 140.2 (s,
3%-C), 133.6 (s, 1%-C), 116.3 (d, 5%-C), 82.3 (s, 6%-C), 60.4
(q, OCH3), 56.2 (q, OCH3), 31.4 (q, COCH3), 25.8 (q,
[CH3]3C)), 18.4 (s, [CH3]3C), −4.36 (q, [CH3]2Si).
h2-(2-Acetyl-3-t-butyldimethylsiloxyphenyl)tetracar-
bonylmanganese (18a) was reacted similarly with ICl,
but because a preliminary test reaction had indicated
very sluggish reaction, the solution was exposed to
strong sunlight for 6 h and then left to stand for 15 h.
There was 43% recovery of unreacted manganated com-
pound and a 45% yield of 2%-t-butyldimethylsiloxy-6%-
iodoacetophenone (18b), a colourless oil, \95% pure
Research funding support from the Research Com-
mittee of the University of Waikato is gratefully ac-
knowledged, as is the scholarship support from the
William Georgetti Foundation to J.M.C.
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