Reactions of [(PPh3)2Pt(η3-CH 2CCPh)]+ with oxygen nucleophiles and chemistry of resultant [(PPH3)2Pt (η3-CH2C(OR)CHPh)]+ complexes

Article abstract of DOI:10.1016/S0022-328X(02)01556-5

The η³-allenyl/propargyl complex [(PPh₃) ₂Pt (η³-CH₂CCPh)]OTf (1OTf) undergoes addition reactions with a number of oxygen nucleophiles in CH₂Cl₂ solution at ambient temperature. With H₂O, it yields the binuclear oxygen-bridged η ³-allyl [{(PPh₃)₂Pt (η³- CH₂CCHPh)}₂O](OTf)₂ (2(OTf) ₂). With primary and secondary alcohols, it rapidly affords the η³-(2-alkoxyallyl) complexes [(PPh₃) ₂Pt(η³-CH₂C(OR) CHPh)]OTf (R = Et (3OTf), i-Pr (4OTf), CH₂CMe₃ (5OTf), CH₂CH=CH₂ (7OTf)), whereas with tertiary alcohols, in slower reactions, it gives both 2(OTf)₂ and [(PPh₃)₂Pt(η³-CH₂C (OR)CHPh)]OTf (R = CMe₃, C(Me)₂Et (6OTf)). There is no reaction at ambient temperature between 1OTf and phenols; however, 1OTf and PhOH afford [(PPh₃)₂Pt(η³- CH₂C(OPh)CHPh)]OTf (8OTf) in the presence of NEt₃. Competition studies reveal the following reactivity order, attributed to steric effects: Me₃CCH₂OH(1.0) 3-(2-alkoxyallyl) complexes react with NaOMe to yield the η³- oxatrimethylemethane product (PPh₃)₂Pt(η ³-CH₂C(O)CHPh)(10), which was also obtained by reaction of 2(OTf)₂ with two equivalents of NaOMe and of 1OTf with NaOH. Complex 10 undergoes conversion to the appropriate [(PPh₃)₂Pt(η³-CH₂C (OR)CHPh)]⁺ with [Et₃O]PF₆, (MeO)₂SO₂ and MeI. The η³- (2-allyloxyallyl) 7OTf reacts with (PPh₃)₂Pt (C₂H₄) to give 10 and [(PPh₃) ₂Pt (η³-CH₂CHCH₂)]OTf; thermolysis of 7OTf in toluene at reflux furnishes [(PPh₃) ₂Pt(η³-CH₂CHCH₂)] OTf, whereas heating in benzene-chloroform affords [(PPh₃) ₂Pt(η³-CH₂C(OCH=CHMe)CHPh)]OTf (11OTf), which results from isomerization of OCH₂CH=CH ₂ to OCH=CHMe. Reaction pathways have been suggested for a number of the aforementioned transformations. All new complexes were characterized by a combination of elemental analysis, FAB mass spectrometry and ¹H-, ¹³C{¹H}- and ³¹P{¹H}-NMR spectroscopy. They were assigned structures in which the η³-allyl oxygen and Ph groups are syn from the ¹H-NMR spectra.

Full text of DOI:10.1016/S0022-328X(02)01556-5

Journal of Organometallic Chemistry 655 (2002) 192ꢂ203
/
www.elsevier.com/locate/jorganchem
Reactions of [(PPh3)2Pt(h3-CH2CCPh)]ꢀ with oxygen nucleophiles
and chemistry of resultant [(PPh3)2Pt(h3-CH2C(OR)CHPh)]ꢀ
complexes
Kirsten L. Daniel, Joan L. Furilla, Andrew Wojcicki *
Department of Chemistry, Newman and Wolfrom Laboratory, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210-1185, USA
Received 8 February 2002; received in revised form 19 April 2002; accepted 19 April 2002
Abstract
The h3-allenyl/propargyl complex [(PPh3)2Pt(h3-CH2CCPh)]OTf (1OTf) undergoes addition reactions with a number of oxygen
nucleophiles in CH2Cl2 solution at ambient temperature. With H2O, it yields the binuclear oxygen-bridged h3-allyl [{(PPh3)2Pt(h3-
CH2CCHPh)}2O](OTf)2 (2(OTf)2). With primary and secondary alcohols, it rapidly affords the h3-(2-alkoxyallyl) complexes
[(PPh3)2Pt(h3-CH2C(OR)CHPh)]OTf (Rꢁ
CMe3, C(Me)2Et (6OTf)). There
is no reaction at ambient temperature between 1OTf and phenols; however, 1OTf and PhOH afford [(PPh3)2Pt(h3-
CH2C(OPh)CHPh)]OTf (8OTf) in the presence of NEt3. Competition studies reveal the following reactivity order, attributed to
/
Et (3OTf), i-Pr (4OTf), CH2CMe3 (5OTf), CH2CHÄ
/
CH2 (7OTf)), whereas with tertiary
alcohols, in slower reactions, it gives both 2(OTf)2 and [(PPh3)2Pt(h3-CH2C(OR)CHPh)]OTf (Rꢁ
/
steric effects: Me3CCH2OH(1.0)B
/
i-PrOH(1.2)B
/
EtOH(2.1)B
MeOH(4.3). The h3-(2-alkoxyallyl) complexes react with NaOMe to
/
yield the h3-oxatrimethylemethane product (PPh3)2Pt(h3-CH2C(O)CHPh) (10), which was also obtained by reaction of 2(OTf)2 with
two equivalents of NaOMe and of 1OTf with NaOH. Complex 10 undergoes conversion to the appropriate [(PPh3)2Pt(h3-
CH2C(OR)CHPh)]ꢀ with [Et3O]PF6, (MeO)2SO2 and MeI. The h3-(2-allyloxyallyl) 7OTf reacts with (PPh3)2Pt(C2H4) to give 10
and [(PPh3)2Pt(h3-CH2CHCH2)]OTf; thermolysis of 7OTf in toluene at reflux furnishes [(PPh3)2Pt(h3-CH2CHCH2)]OTf, whereas
heating in benzeneꢂ
/
chloroform affords [(PPh3)2Pt(h3-CH2C(OCHÄ
/CHMe)CHPh)]OTf (11OTf), which results from isomerization
of OCH2CHÄCH2 to OCHÄ
/
/
CHMe. Reaction pathways have been suggested for a number of the aforementioned transformations.
All new complexes were characterized by a combination of elemental analysis, FAB mass spectrometry and H-, 13C{1H}- and
31P{1H}-NMR spectroscopy. They were assigned structures in which the h3-allyl oxygen and Ph groups are syn from the 1H-NMR
spectra. # 2002 Elsevier Science B.V. All rights reserved.
1
Keywords: Platinum complexes; h3-Allenylꢂ
/
propargyl; h3-(2-Alkoxyallyl); h3-Oxatrimethylenemethane; Nucleophilic addition; Rearrangement
1. Introduction
(NuH or Nu) have been shown to add to the central
carbon atom of the h3-CH2CCR ligand in cationic metal
h3-Allenyl/propargyl complexes represent a growing
class of organotransition-metal compounds [1ꢂ5]. Re-
complexes to afford isolable h3-allyl (Eq. 1) or metalla-
cyclobutene (Eq. 2) products. Reactive oxygen nucleo-
philes include water [5,7a,7b,7e], alcohols [5,7b,7c,7d],
phenols [7c] and carboxylic acids [2], with [Cp*Re-
/
cent advances in this field include the rapidly developing
chemistry of the h3 coordinated allenyl/propargyl ligand
(h3-CH2CCR) that features addition of a variety of
nucleophilic reagents [1,2,5,6]. A number of oxygen
[2,5,7], nitrogen [2,5,7d,7e,8], carbon [2,5,9], sulfur [7c],
selenium [7c] and phosphorus [2,5,7a,8b] nucleophiles
(CO)2(h3-CH2CCH)]ꢀ
[5],
[(h6-C6HnMe6ꢃn)Mo-
(CO)2(h3-CH2CCH)]ꢀ [7a], [(PPh3)2Pt(h3-CH2CCR)]ꢀ
[5,7b,7c,7d,7e] and [(PPh3)2Pd(h3-CH2CCR)]ꢀ [7d] re-
presenting the investigated substrate complexes.
Our group has reported that [(PPh3)2Pt(h3-
CH2CCR)]ꢀ (Rꢁ
Ph (1), Me) react with MeOH to
/
afford the appropriate h3-(2-methoxyallyl) complexes
[(PPh3)2Pt(h3-CH2C(OMe)CHR)]ꢀ [7d]. We now pre-
sent our results of a study on reactions of 1 with other
* Corresponding author. Tel.:
2921685
E-mail address: wojcicki@chemistry.ohio-state.edu (A. Wojcicki).
ꢀ
/
1-614-2924750; fax:
ꢀ/1-614-
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 5 5 6 - 5

K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ
/203
193
CH2CCPh)]OTf (1OTf) [7d] were synthesized as re-
ported in the literature.
2.3. .Reactions of [(PPh3)2Pt(h3-CH2CCPh)]OTf
(1OTf) with oxygen nucleophiles
ð1Þ
ð2Þ
2.3.1. Reaction of 1OTf with water
To a stirred solution of 1OTf (0.179 g, 0.182 mmol) in
10 ml of CH2Cl2 at room temperature (r.t.) was added a
large excess (0.1 ml, ca. 6 mmol) of H2O. The mixture
was stirred for 4 days, the volatiles were removed under
reduced pressure and the light beige residue was
recrystallized from 100 ml of 2:3 (by volume) C6H6ꢂ
/
C5H12. The yield of [{(PPh3)2Pt(h3-CH2CCHPh)}2-
O](OTf)2 (2(OTf)2), a white solid, was 0.145 g (80%).
alcohols and with phenols and water; these results differ
somewhat from and expand on those of Chen and
coworkers [7c] for the related [(PPh3)2Pt(h3-
CH2CCH)]ꢀ containing unsubstituted h3-CH2CCH in
place of h3-CH2CCPh. Also presented here is reaction
chemistry of the [(PPh3)2Pt(h3-CH2C(OR)CHPh)]ꢀ
products which features formation of the platinum h3-
1
IR (Nujol): no n(OH) at 3650ꢂ
(CD2Cl2): d 7.5ꢂ
JPtH 47 Hz, 2H, CHPh), 3.3 (m, 2 H, syn-CHH), 2.4
(m, JPtH
55 Hz, 2H, anti-CHH). 31P{1H}-NMR
(CD2Cl2): d 19.6 (d, JPP 10 Hz, JPtP 3652 Hz),
15.7 (d, JPP 10 Hz, JPtP 3861 Hz). Anal. Found: C,
/
3250 cmꢃ1. H-NMR
/6.4 (m, 70H, Ph), 4.0 (d, JPH
ꢁ11 Hz,
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
55.42; H, 4.10. Calc. for C92H76F6O7P4Pt2S2: C, 55.62;
H, 3.97%.
oxatrimethylenemethane
complex
(PPh3)2Pt(h3-
CH2C(O)CHPh) as well as rearrangements of some
[(PPh3)2Pt(h3-CH2C(OR)CHPh)]ꢀ. Aspects of this in-
vestigation were communicated earlier [7e,10].
2.3.2. Reaction of 1OTf with ethyl alcohol
Ethyl alcohol (1.5 ml, 26 mmol) was added to a stirred
solution of 1OTf (0.150 g, 0.152 mmol) in 3 ml of
CH2Cl2 at r.t. After 5 min, all volatiles were removed
under vacuum, and the residue was dissolved in 3 ml of
CH2Cl2. Hexane (30 ml) was added to induce the
precipitation of a beige product. The volume of the
mixture was reduced to 15 ml, and the light beige solid
was collected on a filter frit and washed with 5 ml of
hexanes. The product [(PPh3)2Pt(h3-CH2C(OEt)CH-
Ph)]OTf (3OTf) was dried under vacuum at 60 8C for
2. Experimental
2.1. General procedures and measurements
Reactions and manipulations of organoplatinum
compounds were carried out under an atmosphere of
dry Ar by use of standard procedures [11]. Solvents were
dried [12], distilled under Ar and degassed before use.
Elemental analyses were performed by Guelph Chemical
Laboratories Ltd. of Canada. M.p.s were measured on a
2 days. Yield: 0.137 g (88%). 1H-NMR (CDCl3): d 7.50ꢂ
6.65 (m, 35H, Ph), 3.93 (d, JPH 10.0 Hz, JPtH 42.6
7.0
9.6 Hz, JHH
6.4 Hz, JPH 4.5
2.8 Hz, 1H, syn-CHH of h3-allyl), 2.50 (dd,
6.4 Hz, JPH 9.5 Hz, JPtH 40.5 Hz, 1H, anti-
CHH of h3-allyl), 1.29 (t, JHH
7.0 Hz, 3H, Me).
13C{1H}/13C-NMR (CDCl3): d 150.6 (s, COEt), 136.3ꢂ
/
ꢁ
/
ꢁ
/
2
3
Hz, 1H, CHPh), 3.72 (dq, JHH
ꢁ
/
9.6 Hz, JHH
ꢁ
/
2
3
Hz, 1H, OCHHMe), 3.54 (dq, JHH
7.0 Hz, OCHHMe), 2.77 (ddd, 2JHH
Hz, JPH
2JHH
ꢁ
/
ꢁ
/
ThomasꢂHoover m.p. apparatus and are uncorrected.
/
ꢁ
/
ꢁ
/
2
IR, NMR (1H, H, 13C and 31P) and FAB mass spectra
were obtained as previously described [13,14].
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
ꢁ
/
3
/
2.2. Materials
/
1
121.5 (m, Ph), 71.5 (dd, JCH
ꢁ
/
149 Hz, JPC
72 Hz, CHPh), 65.8 (t, JCH 147 Hz, CH2Me),
35 Hz, JPtC 132 Hz,
128 Hz, Me). 31P{1H}-NMR
10.5 Hz, JPtP 3758 Hz), 14.1
3769 Hz). FAB MS: 195Pt, m/z
ꢁ
/37 Hz,
1
Reagents were procured from various commercial
sources and used as received, except as noted below.
Methyl alcohol was distilled, first from CaH2 after
heating for 24 h at reflux, and then from sodium. Ethyl
alcohol from a newly opened bottle of absolute grade
was distilled from Mg(OEt)2. Both t-butyl alcohol and
t-amyl alcohol (1,1-dimethylpropanol) were distilled
from CaH2 after heating for 48 h at reflux. Phenol and
neopentyl alcohol were purified by sublimation at
ambient temperature (33 and 760 torr, respectively).
The complexes (PPh3)2Pt(C2H4) [15] and [(PPh3)2Pt(h3-
JPtC
51.4 (td, JCH
CH2CO), 14.5 (q, JCH
(CDCl3): d 18.5 (d, JPP
ꢁ
/
ꢁ
/
1
ꢁ
/
158 Hz, JPC
ꢁ
/
ꢁ
/
1
ꢁ
/
ꢁ
/
ꢁ
/
(d, JPP
ꢁ/10.5 Hz, JPtP
ꢁ
/
880 (Mꢀ), 719 (Pt(PPh3)2ꢀ).
The foregoing reaction was also conducted on a
1
smaller scale by using 1OTf and EtOD. The H-NMR
spectrum (in CDCl3) of the product [(PPh3)2Pt(h3-
CH2C(OEt)CDPh)]OTf (3-d1OTf) was identical with
that of 3OTf except for the absence of the signal of

194
K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ203
/
CHPh. 2H-NMR (CH2Cl2): d 7.0 (br s, Ph-d1, nat.
abund.), 5.0 (br s, CHDCl2, nat. abund.), 3.9 (br d,
CDPh).
Et(Me)2COH (2.8 ml, 26 mmol), and the reaction
contents were stirred for an additional hour at r.t.
before evaporation to dryness under reduced pressure.
The yellow residue was treated with 0.2 ml of CH2Cl2,
and the mixture was filtered. The collected white solid
was identified as [{(PPh3)2Pt(h3-CH2CCHPh)}2-
2.3.3. Reaction of 1OTf with isopropyl alcohol
Isopropyl alcohol (0.45 ml, 5.9 mmol) was added via
gas-tight syringe to a stirred solution of 1OTf (0.199 g,
0.202 mmol) in 3 ml of CH2Cl2. The resulting solution
was stirred for 20 min at r.t., and the solvent and excess
alcohol were removed under reduced pressure to leave a
pale green solid. The residue was dissolved in 2 ml of
CH2Cl2, and addition of 25 ml of hexanes resulted in the
precipitation of a pale yellow product. The solid was
1
O](OTf)2 (2(OTf)2) by H- and 31P{1H}-NMR spectro-
scopy. The filtrate was evaporated to a yellow residue,
which was washed with hexanes (3ꢄ10 ml) and then
/
dissolved in 0.1 ml of C6H6 and precipitated from
solution by addition of 20 ml of Et2O. The yellow solid
was washed with Et2O (2ꢄ5 ml) and dried under
/
vacuum at r.t. for 2 h. Yield of [(PPh3)2Pt(h3-
CH2C(OC(Me)2Et)CHPh)]OTf (6OTf), 0.0127 g (19%).
collected on a filter frit, washed with hexanes (3ꢄ5 ml)
/
and dried under vacuum at 50 8C for 3 days. Yield of
1H-NMR (CDCl3): d 7.5ꢂ
/
6.2 (m, 35H, Ph), 4.47 (d,
37.5 Hz, 1H, CHPh), 3.25 (d,
35.8 Hz, 1H, anti-CHH), 2.92 (br
[(PPh3)2Pt(h3-CH2C(O-i-Pr)CHPh)]OTf (4OTf), 0.188 g
JPH
JPH
ꢁ
/
9.9 Hz, JPtH
9.7 Hz, JPtH
ꢁ
/
(89%). 1H-NMR (CDCl3): d 7.5ꢂ
/
6.5 (m, 35H, Ph), 4.48
41.6 Hz, CHPh), 4.12 (m, 1H,
CHMe2), 3.22 (dd, JHH 6.6 Hz, JPH 10.0 Hz,
JPtH 35.3 Hz, 1H, anti-CHH), 2.73 (br s, 1H, syn-
CHH), 1.38 (d, JHH
3JHH 6.1 Hz, 3H, Me). 13C{1H}-NMR (CDCl3): d
150 (s, JPtC 9.4 Hz, CO-i-Pr), 135ꢂ120 (m, Ph), 73.3
(s, CHMe2), 72.3 (d, JPC 35.6 Hz, JPtC 70.8 Hz,
CHPh), 51.6 (d, JPC 35.8 Hz, JPtC 139 Hz, CH2),
21.9 (s, Me), 20.9 (s, Me). 31P{1H}-NMR (CH2Cl2): d
18.8 (d, JPP 10.4 Hz, JPtP 3750 Hz), 14.3 (d, JPP
10.4 Hz, JPtP
ꢁ
/
ꢁ
/
(d, JPH
ꢁ
/
10.3 Hz, JPtH
ꢁ
/
s, 1H, syn-CHH), 1.64 (br q, 2H, OC(Me)2CH2), 1.32,
2
3
ꢁ
/
ꢁ
/
1.30 (2s, 3H, 3H, OC(Me)2), 0.93 (t, JHH
3H, OC(Me)2CH2Me). 31P{1H}-NMR (CH2Cl2): d 19.0
(d, JPP 8.8 Hz, JPtP 3737 Hz), 14.9 (d, JPP 8.8 Hz,
JPtP 3886 Hz).
ꢁ
/
13.4 Hz,
ꢁ
/
3
ꢁ/6.1 Hz, 3H, Me), 1.23 (d,
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
/
ꢁ
/
ꢁ
/
2.3.6. Reaction of 1OTf with allyl alcohol
ꢁ
/
ꢁ
/
Allyl alcohol (0.45 ml, 2.9 mmol), dried over MgSO4,
was added dropwise with stirring via gas-tight syringe
over 5 min to a solution of 1OTf (0.0738 g, 0.075 mmol)
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
3832 Hz). FAB MS: 195Pt, m/z 894
in 8 ml of CH2Cl2 at ꢃ
/
15 8C. The reaction mixture was
(Mꢀ), 719 (Pt(PPh3)ꢀ): Anal. Found: C, 55.61; H, 4.45.
stirred for 30 min at ꢃ
/
15ꢂ 10 8C. All volatiles were
/
ꢃ
/
2
Calc. for C49H45F3O4P2PtS: C, 56.37; H, 4.34%.
removed under reduced pressure as the reaction mixture
was allowed to warm to ambient temperature. The
resulting green residue was dissolved in 0.3 ml of
CH2Cl2 and precipitated from solution by addition of
30 ml of Et2O. The pale green residue was collected on a
2.3.4. Reaction of 1OTf with neopentyl alcohol
Freshly sublimed Me3CCH2OH (0.11 g, 1.3 mmol)
dissolved in 0.5 ml of CH2Cl2 was added via gas-tight
syringe to a stirred solution of 1OTf (0.0514 g, 0.052
mmol) in 1.5 ml of CH2Cl2, and the resulting reaction
mixture was stirred for 30 min at r.t. The rest of the
procedure followed that in Section 2.3.3 to afford 0.0515
filter frit, washed with Et2O (2ꢄ
vacuum at r.t. for 5 h. Yield of [(PPh3)2Pt(h3-
CH2C(OCH2CHÄCH2)CHPh)]OTf (7OTf), 0.075
(95%). H-NMR (CDCl3): d 8.0ꢂ6.5 (m, 35H, Ph), 5.9
(m, 1H, CH ÄCH2), 5.2 (m, 2H, CHÄCH2), 4.48 (d,
JPH 10.0 Hz, JPtH 39.3 Hz, 1H, CHPh), 4.2 (dq,
3JHH
5.0 Hz, 2H, OCH2), 3.16 (dd, JHH ca. 6 Hz,
JPH 9.9 Hz, JPtH
23.5 Hz, 1H, anti-CHH of h3-
allyl), 2.70 (br s, 1H, syn-CHH of h3-allyl). 13C{1H}-
NMR: d 150 (s, JPtC 9.4 Hz, COCH2), 135ꢂ120 (m,
Ph), 119 (s, CHÄCH2), 72.5 (d, JPC 35.2 Hz, JPtC
69.8 Hz, CHPh), 69.7 (s, OCH2), 52.0 (d, JPC 45.3 Hz,
JPtC CH may be
118.2 Hz, CH2CO) (Signal of CH2Ä
masked by Ph resonances). 31P{1H}-NMR (CH2Cl2): d
18.4 (d, JPP 10.4 Hz, JPtP 3797 Hz), 13.9 (d, JPP
10.4 Hz, JPtP
3833 Hz). FAB MS: 195Pt, m/z 892
(Mꢀ), 719 (Pt(PPh3)ꢀ2 ):
/5 ml), and dried under
/
g
1
/
g
(92%) of [(PPh3)2Pt(h3-CH2C(OCH2CMe3)CH-
Ph)]OTf (5OTf) as a pale green solid. 1H-NMR
(CDCl3): d 7.5ꢂ6.5 (m, 35H, Ph), 4.5 (d, JPH 10.5
Hz, JPtH 8.7 Hz,
38.5 Hz, 1 H, CHPh), 3.4 (d, 2JHH
1H, CHHCMe3), 3.35 (dd, 2JHH
6.6 Hz, JPH
JPtH 36.2 Hz, 1H, anti-CHH), 3.1 (d, JHH
/
/
ꢁ
ꢁ
/
ꢁ
/
2
/
ꢁ
/
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
9.4 Hz,
2
ꢁ
/
ꢁ
/
8.7 Hz,
ꢁ
/
/
1H, CHHCMe3), 2.9 (br s, 1H, syn-CHH), 1.0 (s, 9H,
Me). 13C{1H}-NMR (CDCl3): d 150 (s, JPtC
8.8 Hz,
COCH2), 135ꢂ120 (m, Ph), 79.2 (s, OCH2), 72.7 (d,
JPC 31.6 Hz, JPtC 74.4 Hz, CHPh), 52.5 (d, JPC 35
Hz, JPtC 125 Hz, CH2CO), 31.5 (s, CMe3), 26.3 (s,
Me). 31P{1H}-NMR (CDCl3): d 18.0 (d, JPP
10.6 Hz,
JPtP 3784 Hz), 13.3 (d, JPP 10.6 Hz, JPtP 3797 Hz).
FAB MS: 195Pt, m/z 922 (Mꢀ), 719 (Pt(PPh3)ꢀ2 ):
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
/
ꢁ
/
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
/
/
2.3.7. Reaction of 1OTf with phenol
2.3.5. Reaction of 1OTF with t-amyl alcohol
A solution of 1OTf (0.0623 g, 0.063 mmol) in 40 ml of
CH2Cl2 was added dropwise over 1 h to freshly distilled
Freshly sublimed PhOH (0.0098 g, 0.10 mmol)
dissolved in 1 ml of CH2Cl2 was added dropwise with
stirring to a solution of 1OTf (0.101 g, 0.103 mmol) in 3

K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ
/203
195
ml of CH2Cl2. The reaction solution was then treated
with a large excess of Et3N (4 drops), resulting in an
immediate change of color from yellow to red. After the
mixture had been stirred for 30 min at r.t., all volatiles
were removed under reduced pressure. The pale yellow
residue (0.107 g) was dissolved in CH2Cl2 (0.4 ml), and
Et2O (50 ml) was added to precipitate a gummy orange
solid. The solvent was removed by syringe, and the
CH2(OMe)CHPh)]OTf (9OTf) and [(PPh3)2Pt(h3-
CH2C(OCH2CMe3)CHPh)]OTf (5OTf), were observed
in the respective mixtures of products by 1H- and
31P{1H}-NMR spectroscopy, with 9OTf being the major
product in each case. The exact ratios of products were
determined from the relative intensities of the signals of
OMe of 9OTf, of the lower-field resonating Me of 4OTf
and of CMe3 of 5OTf.
residue was washed consecutively with Et2O (2ꢄ
/
50 ml),
C6H5Me (2ꢄ30 ml) and THF (2ꢄ5 ml) to furnish a
/
/
2.5. Preparation of (PPh3)2Pt(h3-CH2C(O)CHPh)
(10)
pale yellow solid which was dried under vacuum at r.t.
for 4 days. Yield of [(PPh3)2Pt(h3-CH2C(OPh)CH-
Ph)]OTf (8OTf), 0.0729 g (66%). H-NMR (CD2Cl2):
1
2.5.1. Reactions of [(PPh3)2Pt(h3-
d 7.5ꢂ
35.4 Hz, 1H, CHPh), 3.3 (dd, JHH ca. 6 Hz, JPH
Hz, JPtH
CHH). 13C{1H}-NMR (CD3OD): d 147 (s, JPtH
Hz, COPh), 135ꢂ120 (m, Ph), 74.6 (d, JPC
JPtC 48.2 Hz, CHPh), 54.6 (d, JPC 33.8 Hz, JPtC
127.3 Hz, CH2CO). 31P{1H}-NMR (CH2Cl2): d 18.9 (d,
JPP 10.2 Hz, JPtP 3764 Hz), 14.2 (d, JPP 10.2 Hz,
JPtP
3983 Hz). FAB MS: 195Pt, m/z 928 (Mꢀ), 719
(Pt(PPh3)ꢀ2 ):
/
6.5 (m, 40H, Ph), 4.85 (d, JPH
ꢁ
/
9.8 Hz, JPtH
ꢁ
/
CH2C(OR)CHPh)]OTf (Rꢁ
i-Pr (4OTf)) with NaOMe
/
Me (9OTf), Et (3OTf),
2
ꢁ/9.5
ꢁ
/
32.9 Hz, 1H, anti-CHH), 2.35 (br s, 1H, syn-
A solution of 9OTf (0.286 g, 0.281 mmol) in 10 ml of
CH2Cl2 was treated with NaOMe (0.015 g, 0.28 mmol)
in ca. 1 ml of MeOH, and the contents were stirred for
ca. 12 h. The mixture was filtered, the filtrate was
evaporated to dryness, and the residue was recrystallized
ꢁ
/
8.9
/
ꢁ33.1 Hz,
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
from CH2Cl2ꢂ/C5H12. The pale beige solid was dried
ꢁ
/
under vacuum at 55 8C for 5 days. Yield of 10: 0.179 g
1
/
(74%), m.p. 208 8C (dec.). H-NMR (CDCl3): d 7.6ꢂ
6.6 (m, 35H, Ph), 3.94 (d, JPH 11.6 Hz, JPtH 80.4 Hz,
1H, CHPh), 2.53 (m, 1H, syn-CHH), 2.33 (m, JPtH 36
Hz, 1H, anti-CHH). 13C{1H}-NMR (CDCl3): d 177.9
(t, JPC 4.9 Hz, JPtC 151 Hz, CO), 135ꢂ123 (m, Ph),
66.7 (dd, JPC 57, 3.6 Hz, JPtC 305 Hz, CHPh), 49.9
(dd, JPC 52, 4.6 Hz, JPtC
305 Hz, CH2). 31P{1H}-
NMR (CDCl3): d 21.3 (d, JPP 5.1 Hz, JPtP 3107 Hz),
19.9 (d, JPP 5.1 Hz, JPtP
2964 Hz). FAB MS: 195Pt,
/
ꢁ
/
ꢁ
/
2.4. Competition reactions of [(PPh3)2Pt(h3-
CH2CCPh)]OTf (1OTf) with ROH and R?OH
ꢁ
/
ꢁ
/
ꢁ
/
/
The reaction of 1OTf with a mixture of MeOH and
EtOH illustrates the procedure employed.
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
A well stirred mixture of MeOH (0.103 ml, 2.6 mmol)
and EtOH (0.150 ml, 2.6 mmol) was added quickly by
syringe to a stirred solution of 1OTf (0.0530 g, 0.054
mmol) in 2 ml of dry CH2Cl2. The resulting solution was
stirred for 20 min at r.t., and then all the volatiles were
removed under reduced pressure. The yellow solid
residue was purified by dissolution in 0.5 ml of
CH2Cl2 and precipitation by addition of 5 ml of
hexanes. The precipitate was dried under vacuum at
r.t. for 2 days. The product mixture was examined by
1H-NMR spectroscopy before and after purification to
ensure that no significant change in composition
occurred as a result of solubility difference. The 1H-
and 31P{1H}-NMR spectra showed the presence of both
[(PPh3)2Pt(h3-CH2C(OMe)CHPh)]OTf (9OTf) [7d] and
[(PPh3)2Pt(h3-CH2C(OEt)CHPh)]OTf (3OTf) in the
mixture, ca. in a 2:1 ratio. The relative intensities of
the signals of CHPh of 9OTf (1.38, 1H) and of Me of
3OTf (1.97, 3H) were used to determine the exact ratio
of the two products.
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
m/z 851 (Mꢀ). Anal. Found: C, 63.26; H, 4.60. Calc. for
C45H38OP2Pt: C, 63.45; H, 4.50%.
Complex 10 was also obtained from 3OTf or 4OTf
and NaOMe by similar procedures.
2.5.2. Reaction of [{(PPh3)2Pt(h3-
CH2CCHPh)}2O](OTf)2 (2(OTf)2 with NaOMe
A solution of NaOMe (0.0094 g, 0.174 mmol, two
equivalents) in 2 ml of MeOH was added with stirring to
2(OTf)2 (0.1727 g, 0.0869 mmol) partially dissolved in 15
ml of CH2Cl2. The resulting solution was stirred for ca.
12 h, all volatiles were removed under reduced pressure
and the residue was dissolved in 1 ml of CH2Cl2. The
31P{1H}-NMR spectrum showed 10 as the only phos-
phorus-containing product.
2.5.3. Reaction of [(PPh3)2Pt(h3-CH2CCPh)]OTf
(1OTf) with KOH
Similar procedures were employed for reactions of
1OTf with mixtures of MeOH and i-PrOH and of
MeOH and Me3CCH2OH. A 50- and a 20-fold excess of
each alcohol over 1OTf was used in the former and the
latter reaction, respectively. Both [(PPh3)2Pt(h3-CH2C-
(OMe)CHPh)]OTf (9OTf) and [(PPh3)2Pt(h3-CH2C(O-
i-Pr)CHPh)]OTf (4OTf), and both [(PPh3)2Pt(h3-
To a solution of 1OTf (0.1535 g, 0.156 mmol) in 20 ml
of CH2Cl2 was added a large excess (typically one pellet)
of KOH, and the mixture was stirred while being
monitored by 31P{1H}-NMR spectroscopy. The reac-
tion reached completion in 10 days. The mixture was
filtered, and the filtrate was evaporated to dryness.
Dissolution in minimal CH2Cl2 and addition of hexanes

196
K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ203
/
induced the precipitation of 10, which was identified
spectroscopically. Yield: ca. 0.11 g (83%).
solid had dissolved, progress of the reaction was
monitored by 31P{1H}-NMR spectroscopy. Conversion
of 7 to a single PtP product, identified as [(PPh3)2Pt(h3-
CH2CHCH2)]ꢀ [17], was complete in ca. 2 days.
In another experiment, 7OTf (0.043 g, 0.041 mmol)
Use of 1:1 (by volume) CH2Cl2ꢂTHF as the solvent
/
decreases reaction time to ca. 24 h owing to increased
solubility of KOH. However, additional THF decreases
solubility of 1OTf to the point that the reaction slows
down.
dissolved in 0.6 ml of 1:5 (by volume) CDCl3ꢂC6D6 in a
/
pyrex tube equipped with a stopcock was heated in an
oil bath at 80 8C for 48 h and then allowed to cool to
r.t. The cloudy yellow solution was treated with 2 ml of
CH2Cl2 to dissolve most of the solid, and the mixture
was filtered. To the filtrate was slowly added with
stirring 30 ml of hexanes to precipitate a pale yellow
solid, which was collected on a filter frit, washed with
2.6. Reactions of (PPh3)2Pt(h3-CH2C(O)CHPh) (10)
with alkylating reagents
2.6.1. Reaction of 10 with [Et3O]PF6
To a solution of 10 (0.0902 g, 0.11 mmol) in 3 ml of
CH2Cl2 was added one equivalent of [Et3O]PF6 (0.0263
g, 0.11 mmol) in 2 ml of CH2Cl2, and the resulting
mixture was stirred at r.t. for 1 h. Examination of the
reaction solution by 31P{1H}-NMR spectroscopy re-
vealed complete conversion to [(PPh3)2Pt(h3-
CH2C(OEt)CHPh)]ꢀ (3).
hexanes (2ꢄ
vacuum. Yield
CHMe)CHPh)]OTf (11OTf), 0.0307 g (71%). H-NMR
/
5 ml) and dried for several hours in
of
[(PPh3)2Pt(h3-CH2C(OCHÄ
/
1
3
(CDCl3): d 8.0ꢂ
1H, OCH), 5.00 (quin, 3JHH ca. 7 Hz, 1H, CHMe), 4.75
(d, JPH 10 Hz, JPtH 33.5 Hz, 1H, CHPh), 3.35 (dd,
2JHH
7 Hz, JPH 10 Hz, JPtH 43 Hz, 1H, anti-
CHH), 3.02 (br s, 1H, syn-CHH), 1.87 (d, 3JHH
7 Hz,
3H, Me). 13C{1H}-NMR (CDCl3): d 146 (s, JPtC
9.0
Hz, COCH), 138 (s, OCH), 135ꢂ125 (m, Ph), 111 (s,
CHMe), 72.5 (d, JPC 33.6 Hz, JPtC 57.8 Hz, CHPh),
53.5 (d, JPC 33.7 Hz, JPtC 123.6 Hz, CH2), 10.0 (s,
Me). 31P{1H}-NMR (CH2Cl2): d 18.1 (d, JPP
9.4 Hz,
JPtP 3876 Hz), 13.7 (d, JPP 9.4 Hz, JPtP 3920 Hz).
/
6.5 (m, 35H, Ph), 6.15 (d, JHH
ꢁ
/
7 Hz,
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
2.6.2. Reaction of 10 with dimethylsulfate
ꢁ
/
A solution of 10 (0.0488 g, 0.057 mmol) in 0.5 ml of
CDCl3 in an NMR tube was treated by syringe with ca.
10-fold excess (0.01 ml) of (MeO)2SO2 at r.t. The
reaction was followed by 31P{1H}-NMR spectroscopy
and went cleanly to completion in ca. 5 h to afford
[(PPh3)2Pt(h3-CH2C(OMe)CHPh)]ꢀ (9).
ꢁ
/
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
ꢁ
/
2.6.3. Reaction of 10 with methyl iodide
A solution containing 10 (0.125 g, 0.15 mmol) and
MeI (0.10 ml, 0.16 mmol) in 10 ml of CH2Cl2 was
maintained at reflux temperature for 12 h and then was
allowed to cool to ambient temperature. The mixture
was filtered, and the filtrate was concentrated to 1 ml.
The 31P{1H}-NMR spectrum indicated the presence of
10 and [(PPh3)2Pt(h3-CH2C(OMe)CHPh)]ꢀ (9) in ca.
3:1 ratio, as well as [Ph3PMe]ꢀ [16].
3. Results and discussion
3.1. Reaction of [(PPh3)2Pt(h3-CH2CCPh)]OTf
(1OTf) with water
Treatment of 1OTf in CH2Cl2 at room temperature
with a large excess of H2O affords the binuclear
[{(PPh3)2Pt(h3-CH2CCHPh)}2O](OTf)2 (2(OTf)2) as a
white solid in 80% yield (Eq. 3).
2.7. Reaction of [(PPh3)2Pt(h3-CH2C(OCH2CHÄ
CH2)CHPh)]OTf (7OTf) with (PPh3)2Pt(C2H4)
/
To
a solution of 0.019 g (0.025 mmol) of
(PPh3)2Pt(C2H4) in 0.1 ml of CDCl3 in an NMR tube
was added by syringe 0.025 g (0.024 mmol) of 7OTf in
0.8 ml of CDCl3, and the contents were shaken for 10
min at r.t. An immediate color change from yellow to
ð3Þ
1
light brown was observed. The H- and 31P{1H}-NMR
spectra showed the presence of 10 and [(PPh3)2Pt(h3-
The product, which is somewhat soluble in CH2Cl2 and
essentially insoluble in CHCl3 and other common
organic solvents, was characterized by 1H- and
31P{1H}-NMR spectroscopy and elemental analysis.
The 1H-NMR signals at d 4.0, 3.3 and 2.4 and the
coupling constants JPH and JPtH (cf. Section 2.3.1) are
characteristic of the CHPh, syn-CHH and anti-CHH
CH2CHCH2)]ꢀ [17] in a 1:1 ratio.
2.8. Thermolysis of [(PPh3)2Pt(h3-CH2C(OCH2CHÄ
CH2)CHPh)]OTf (7OTf)
/
A slurry of 7OTf (0.1027 g, 0.099 mmol) in C6H5Me
(50 ml) was heated at reflux with vigorous stirring in a
flask equipped with a reflux condenser. After all the
protons,
respectively,
in
various
complexes
O-donor group)
[(PPh3)2Pt(h3-CH2C(X)CHPh)]ꢀ (Xꢁ
/

K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ
/203
197
where X and Ph are syn [7d,7e,10]. In the 31P{1H}-
NMR spectrum two signals are observed, at d 19.6 and
CH2CCH)]ꢀ [7a] and [Cp*Re(CO)2(h3-CH2CCH)]ꢀ
[5], where the h3-(2-hydroxyallyl) products were ob-
tained instead. However, the reaction with H2O of
[(PPh3)2Pt(h3-CH2CCH)]ꢀ, the unsubstituted h3-
CH2CCH analog of 1, afforded both [{(PPh3)2Pt(h3-
15.7, with JPP
ꢁ
/
10 Hz and JPtP
ꢁ3652 and 3861 Hz,
/
also in the ranges expected for [(PPh3)2Pt(h3-
CH2C(X)CHPh)]ꢀ [7d,7e,10]. The absence of a n(OH)
absorption in the IR spectrum rules out the formulation
of 2 as a 2-hydroxyallyl complex, [(PPh3)2Pt(h3-
CH2C(OH)CHPh)]ꢀ. The assigned structure is further
supported by treatment of 2 with two equivalents of
NaOMe to afford 10 (cf. Section 3.3) as the only Pt
complex (Eq. 4).
CH2CCH2)}2O]2ꢀ
and
[(PPh3)2Pt(h3-CH2C(OH)-
CH2)]ꢀ in the relative amounts that varied with experi-
mental conditions [7b]. The observation of the oxo-
bridged binuclear platinum product in that study as well
as in the present work may be explained by the initial
formation of a h3-(2-hydroxyallyl) complex and its
subsequent rapid reaction with the h3-allenyl/propargyl
reagent (Eq. 5). In fact, reaction of [(PPh3)2Pt(h3-
CH2CCH)]ꢀ with [(PPh3)2Pt(h3-CH2C(OH)CH2)]ꢀ
was
shown
to
produce
[{(PPh3)2Pt(h3-CH2-
CCH2)}2O]2ꢀ [7b].
3.2. Reactions of [(PPh3)2Pt(h3-CH2CCPh)]OTf
(1OTf) with alcohols and phenols
ð4Þ
Reaction of 1OTf with a large excess of the primary or
secondary alcohol EtOH, i-PrOH or Me3CCH2OH in
CH2Cl2 solution occurs within minutes at room tem-
perature to afford the appropriate h3-(2-alkoxyallyl)
complex [(PPh3)2Pt(h3-CH2C(OR)CHPh)]OTf (Rꢁ
/
Et
(3OTf), i-Pr (4OTf) or Me3CCH2 (5OTf)) as a light
yellow or beige solid in ca. 90% isolated yield (Eq. 6).
The
ð6Þ
ð5Þ
corresponding reaction of 1OTf with CH2Ä
in CH2Cl2, conducted similarly but at ꢃ15ꢂ
gave [(PPh3)2Pt(h3-CH2C(OCH2CHÄ
CH2)CHPh)]OTf
/CHCH2OH
/
/
ꢃ
/
10 8C,
/
(7OTf) essentially quantitatively. In contrast, the ter-
tiary alcohols Et(Me)2COH and Me3COH require
longer than an hour to completely react with 1OTf at
ambient temperature and afford both 2(OTf)2 and the
appropriate h3-(2-alkoxyallyl) complex [(PPh3)2Pt(h3-
Reaction of 1OTf with H2O under various other
conditions, for example, use of equimolar amounts of
the reactants in CH2Cl2ꢂTHF, also yielded 2(OTf)2. No
/
evidence was obtained for the presence of a h3-(2-
hydroxyallyl) product. These results stand in contrast to
those obtained for aquation of other h3-allenyl/propar-
gyl complexes, viz. [(h6-C6HnMe6ꢃn)Mo(CO)2(h3-
CH2C(OR)CHPh)]OTf (Rꢁ
/
Et(Me)2C (6OTf), Me3C)
(Eq. 7).

198
K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ203
/
ð7Þ
The yield of the h3-(2-alkoxyallyl) complex can be
optimized (ca. 1:1 alkoxyallyl/2) by slow addition of a
dilute solution of 1OTf in CH2Cl2 to a large excess of
the alcohol. Phenol, p-methoxyphenol and p-nitrophe-
nol do not react with 1OTf in CH2Cl2 at room
temperature over several hours. However, addition of
triethylamine in excess to a CH2Cl2 solution of phenol
and 1OTf gives [(PPh3)2Pt(h3-CH2C(OPh)CHPh)]OTf
(8OTf) as a pale yellow solid in 66% yield in ca. 30 min
(Eq. 8). Interestingly, [(PPh3)2Pt(h3-CH2CCH)]ꢀ, the
unsubstituted h3-CH2CCH analog of 1, reacts with
ð9Þ
Complexes 3OTfꢂ8OTf were characterized by a
/
combination of IR and NMR (1H, 13C{1H} and
31P{1H}) spectroscopy, FAB mass spectrometry and
elemental analysis. All of the FAB mass spectra showed
1
a strong peak corresponding to m/z for (Mꢀ). The H-
and 13C{1H}-NMR spectra are consistent with the
presence of a h3-CH2C(OR)CHPh ligand in which the
OR and Ph groups are syn. Accordingly, proton
resonances occur in the ranges d 4.85ꢂ
/
3.93 (d, JPH
35.4ꢂ42.6 Hz),
9.4ꢂ10.0 Hz,
40.5 Hz) and 2.92ꢂ2.35
ꢁ
/
9.8ꢂ
/
10.5 Hz, with 195Pt satellites, JPtH
ꢁ
/
/
ð8Þ
2
3.35ꢂ
/
2.50 (dd, JHH ca. 6ꢂ
/
6.6 Hz, JPH
ꢁ
/
/
with 195Pt satellites, JPtH
ꢁ
/
23.5ꢂ
/
/
(generally, br s). They are assigned to CHPh, anti-CHH
and syn-CHH, respectively. These assignments receive
support from the following observations: (i) the presence
of substantial 195PtÃ
signals at d 4.85ꢂ3.93 and 3.35ꢂ
positions for both protons [18]; (ii) an appreciable value
of JHH (6ꢂ6.6 Hz) for the resonance at d 3.35ꢂ2.50,
/
H coupling (vide supra) for the
2.50, which suggest anti
phenol in the absence of base, albeit more slowly than
with primary or secondary alcohols or with Me3COH,
to give [(PPh3)2Pt(h3-CH2C(OPh)CH2)]ꢀ [7c].
/
/
/
/
The h3-(2-alkoxyallyl) complexes 3OTf, 4OTf, 5OTf
and the previously reported [7d] [(PPh3)2Pt(h3-CH2C(O-
Me)CHPh)]OTf (9OTf) are thermally stable com-
pounds. For example, 4OTf undergoes only slight
decomposition when heated in THF at reflux tempera-
ture for 2 months (monitored by 31P-NMR spectro-
scopy). Furthermore, heating 4OTf in water results in
very little decomposition. The h3-(2-alkoxyallyl) com-
plexes also remain intact upon prolonged contact with
alcohols; for example, there is no reaction between 9OTf
and ethyl alcohol at ambient temperatures over ca. 2
days. However, the h3-(2-phenoxyallyl) 8OTf reacts
with methyl alcohol on heating to give 9OTf (Eq. 9);
there is also slow reaction at room temperature.
which is attributed to geminal coupling; and (iii) the
absence of W-coupling [19] expected for syn allylic
hydrogens of C1 and C3, which was ascertained by
selective decoupling experiments on 3OTf. The fore-
1
going H-NMR data are in good agreement with those
obtained for the h3-(2-methoxyallyl) complex 9OTf,
where the same orientation of OR and Ph was inferred
[7d].
In the 31C{1H}-NMR spectra, resonances of the h3-
allyl COR, CHPh and CH2 carbon atoms are observed
at d 150ꢂ
Whereas the CHPh and CH2 signals appear as doublets
owing to phosphorusꢂcarbon coupling involving one
PPh3 ligand (JPC 31.6ꢂ37 and 33.8ꢂ45.3 Hz, respec-
/
147, 74.6ꢂ
/
71.5 and 54.6ꢂ
/
51.4, respectively.
/
ꢁ
/
/
/

K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ
/203
199
tively), no such interaction is evident for the COR
carbon. All three signals generally occur with observable
cal evidence. However, the mechanism by which the co-
product 2(OTf)2 arises is less apparent. This binuclear
complex might be generated by reaction of 1OTf with
water present in the alcohol, although such a possibility
would appear unlikely since the alcohol was carefully
dried and purified as reported in Section 2.2. Alterna-
tively, 2(OTf)2 could arise from reaction of 1OTf with a
h3-(2-hydroxyallyl) complex, [(PPh3)2Pt(h3-CH2C(OH)-
CHPh)]OTf (cf. Eq. 5), generated in the reaction.
Formation of the latter would require elimination of
alkene from the reacting alcohol. This could possibly
occur by initial addition of ROH to the central carbon
atom of h3-CH2CCPh followed by agostic interaction of
the alcohol b-H with the metal leading to formation of
195Pt satellites: JPtC
ꢁ
/
8.8ꢂ
/
9.4 Hz for COR, 48.2ꢂ74.4
/
Hz for CHPh and 118.2ꢂ/139 Hz for CH2. Again, there
is good accord with corresponding data for related
platinum complexes [7b,7c,7d,8c,9a].
1
Among further noteworthy features in the H- and
13C{1H}-NMR spectra of complexes 3OTfꢂ
8OTf is
/
diastereotopy of the otherwise equivalent nuclei owing
to the presence of the chiral CC(Pt)HPh center. As a
result, two signals are observed for each of OCH2Me of
3OTf, OCHMe2 of 4OTf, OCH2CMe3 of 5OTf,
OC(Me)2Et of 6OTf and OCH2CHÄ
/
CH2 of 7OTf in
1
the respective H-NMR spectra, and for OCHMe2 of
4OTf in the 13C{1H}-NMR spectrum. The 31P{1H}-
PtÃ/H and elimination of appropriate alkene. Transfer of
NMR spectra consist of two doublet signals (JPP
10.6 Hz) at d 19.0ꢂ18.0 and 14.3ꢂ
13.3 with 195Ptꢂ
coupling (JPtP 3737ꢂ3983 Hz) as a result of the
ꢁ
/
8.8ꢂ
/
this hydrogen to the CPh carbon atom would then
afford such a h3-(2-hydroxyallyl) intermediate. This
sequence of transformations is set out in Scheme 2.
Several experiments were performed to shed light on
the aforementioned proposal. Intermediate A in Scheme
2 has two possible sources of H for transfer to produce
the 2-alkoxyallyl or 2-hydroxyallyl: the hydroxyl H (cf.
Scheme 1) and alkyl b-H, respectively. If the reaction is
carried out in the presence of a non-nucleophilic base,
then one could generate a deprotonated form of A, and
the hydroxylic hydrogen would no longer be available
for transfer to give the h3-(2-alkoxyallyl). Accordingly it
was found that if 1OTf and t-amyl alcohol were allowed
to react in the presence of NEt3 in excess, only the
elimination product 10 was obtained (Eq. 10). However,
the
/
/
/P
ꢁ
/
/
terminal carbon atoms of h3-allyl being in different
environments. For the h3-(2-allyloxyallyl) complex
7OTf, the 1H- and 13C{1H}-NMR signals of the
OCH2CHÄ/CH2 group are similar in position and
appearance to those of allyl alcohol. The coupling
constants and splitting patterns given in Section 2.3.6
were elucidated by selective decoupling experiments.
A mechanism consistent with the anti addition of
MeOH to the h3-CH2CCPh of 1 was proposed earlier
(Scheme 1) [7d]. Briefly, it involves: (i) attack of MeOH
at the central carbon atom to generate a methoxy-
substituted metallacyclobutene intermediate; (ii) loss of
the OH proton to the platinum center; and (iii) transfer
of this hydrogen to the CPh carbon atom away from the
OMe group. This general pathway has also been
suggested for addition of ROH to other metal h3-
allenyl/propargyl complexes [2,5] and applies to the
reactions of 1OTf with the primary and secondary
alcohols investigated here (Eq. 6) because of a similar
stereochemical outcome. Treatment of 1OTf with EtOD
affords 3-d1OTf where the D atom is positioned anti to
1
2
ð10Þ
OEt, as inferred from the H- and H-NMR spectra.
This result is consistent with the aforementioned me-
chanism and indicates that no scrambling of ligand
hydrogens occurs during the addition of alcohol.
The formation of the h3-(2-alkoxyallyl) complexes in
the reaction of 1OTf with tertiary alcohols (cf. Eq. 7)
likely proceeds by a similar pathway from stereochemi-
Scheme 1.

200
K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ
/203
Scheme 2.
h3-(2-t-amyloxyallyl) 6OTf reacts neither with NEt3 nor
with [HNEt3][OC(Me)2Et]. Thus the elimination to give
10 must be occurring at some intermediate stage of the
reaction in Eq. 10, and not from the product 6.
To further test the foregoing mechanism of formation
of 2(OTf)2 from 1OTf and t-amyl alcohol, attempts
were made at detection of 2-methylbut-1-ene or 2-
methylbut-2-ene during the reaction. However, 1H-
NMR spectra of the volatile organic mixture showed
no evidence of vinylic hydrogens of an alkene. Because
of this result, the question of mechanism remains
unresolved.
CH2C(O)CHPh) (10) (Eq. 11). Similar results were
obtained by using the h3-(2-ethoxyallyl)
ð11Þ
The relative reactivity of 1OTf toward various alco-
hols was determined by competition studies using
mixtures of two alcohols as described in Section 2.4.
These experiments showed that the rate of reaction at
ambient temperature increases in the order
(3OTf), h3-(2-isopropoxyallyl) (4OTf) and h3-(2-t-amy-
loxyallyl) (6OTf) complexes in place of 9OTf. Also, in
related work, Kurosawa, Ikeda and coworkers em-
ployed reactions of [(PPh3)2M(h3-CH2C(OCH2O-
Me3CCH2OHB
/
i-PrOHB
/
EtOHBMeOH in the ratios
/
Me)CH2)]X (Mꢁ
/
Pd, Pt; XꢁCl, PF6) with NaOMe
/
or NaOH to synthesize (PPh3)2M(h3-CH2C(O)CH2)
1.0:1.2:2.1:4.3. The difference in reactivity among the
four alcohols is quite modest and may be attributed to
their steric properties. Interestingly, in a parallel study
Chen and coworkers reported [7c] that the order of
reactivity in the addition of alcohols to [(PPh3)2Pt(h3-
[20]. In all of these transformations, the metal h3-
(CH2C(OR)CHR?) (R?ꢁPh, H) complex behaves as
/
an alkyloxonium salt, readily losing its oxygen-bound
Rꢀ. A reported variation on this methodology is
deprotonation of cationic metal h3-(2-hydroxyallyl)
complexes [20,21]. In the present study, complex 10
was also prepared by reaction of 2(OTf)2 with two
equivalents of NaOMe (cf. Eq. 4) and of 1OTf with
KOH (Eq. 12). Of the methods reported
CH2CCH)]BF4 follows
a
similar pattern, viz.
Me3COHBi-PrOHBEtOHB
/
/
/MeOH, with the relative
rates being 1.0:5.8:10.0:17.5. The quantitative rate
profiles of the two platinum h3-allenyl/propargyl com-
plexes are almost identical for MeOH, EtOH and i-
PrOH. In contrast, Me3COH, which reacts only ca. six
times more slowly than i-PrOH with [(PPh3)2Pt(h3-
CH2CCH)]BF4, is significantly less reactive than i-
PrOH toward 1OTf. This greater difference in reactivity
observed for the latter complex may be a result of
considerable steric repulsion between the phenyl group
of its h3-CH2CCPh ligand and the bulky Me3COH.
3.3. Preparation and reactions of (PPh3)2Pt(h3-
CH2C(O)CHPh) (10)
ð12Þ
here, the one of choice is that presented in Eq. 10
because of simplicity, purity of product and high yield.
1
In an attempt to introduce another methoxy group, in
a terminal position of the h3-hydrocarbyl ligand of
[(PPh3)2Pt(h3-CH2C(OMe)CHPh)]ꢀ (9), 9OTf was al-
Complex 10 was characterized by H-, 13C{1H}- and
31P{1H}-NMR spectroscopy, FAB mass spectrometry
and elemental analysis. The NMR data show strong
similarities to the corresponding data of the precursor
h3-(2-alkoxyallyl) complexes, except for the absence of
the appropriate signals of OR. The appearance of three
lowed to react with NaOMe in CH2Cl2ꢂMeOH. How-
/
ever, instead of addition of OMeꢃ, dealkylation of the
OMe of 9 took place to afford the platinum h3-
oxatrimethylenemethane
complex
(PPh3)2Pt(h3-

K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ
/203
201
Scheme 3.
proton resonances of h3-CH2C(O)CHPh at d 3.94, 2.53
and 2.33, two with the relatively large coupling con-
stants JPtH of 80 and 34 Hz, indicates that the Ph group
is syn to the oxygen [18], as for the h3-(2-alkoxyallyl)
complexes. The 13C{1H}-NMR signals of CO, CHPh
and CH2 occur at d 177.9 (t, 151), 66.7 (dd, 305) and
slipped metal h3-allyl and puckered metallacyclic reso-
nance structures [7e,22]. This conclusion is derived from
X-ray structural [20,21] and NMR spectroscopic studies
[7d,10,20,21]. Interestingly, unlike most of the L2Pt(h3-
oxatrimethylenemethane) complexes, 10 shows stereo-
1
chemically rigid behavior in its H- and 13C{1H}-NMR
49.9 (dd, 305), respectively, with observable spinꢂ
/
spin
spectra at ambient temperatures. However, the com-
plexes L2Pt(h3-CH(R)C(O)CHR) investigated by Kem-
mitt and coworkers generally undergo scrambling of the
syn and anti groups of CHR, and this observed
fluxionality has been attributed to inversion of the
puckered metallacyclic ring [21,22].
coupling to both 195Pt (given in Hz in parentheses) and
31P. In general, the NMR spectroscopic data of 10
compare well with those of a series of complexes
L2Pt(h3-CH(R)C(O)CHR) (Lꢁ
/
PPh3, AsPh3, other
H, Ph, C(O)Me, CO2Me), ob-
1
2
phosphines, bipy; Rꢁ
/
Complex 10 undergoes alkylation to regenerate
[(PPh3)2Pt(h3-CH2C(OR)CHPh)]ꢀ. Thus, ethylation
has been effected essentially quantitatively by use of
[Et3O]PF6 in CH2Cl2 at room temperature (Eq. 13), and
methylation by use of an excess of (MeO)2SO2 in
tained by Kemmitt and coworkers [21,22] via synthetic
methods very different from those developed in this
study.
The bonding in these platinum oxatrimethylene-
methane complexes is best described as a hybrid of
Scheme 4.

202
K.L. Daniel et al. / Journal of Organometallic Chemistry 655 (2002) 192ꢂ203
/
CDCl3, also at
(CHPh), 3.35 (anti-CHH) and 3.02 (syn-CHH) and the
13C{1H}-NMR signals at d 146 (COCH), 72.5 (CHPh)
and 53.5 (CH2) are similar in position and splitting
pattern to those of the other platinum h3-
CH2C(OR)CHPh complexes prepared in this study.
1
The remaining H and 13C{1H} resonances of the h3-
CH2C(OR)CHPh ligand are in accord with the OR
group being OCHÄ
/
CHMe, which resulted from isomer-
ization of the OCH2CHÄ
/
CH2 in 7. Organic CÄC double
/
bond isomerization is quite commonly effected by
platinum and other metal catalysts [26]. Further heating
of 11OTf in benzene at reflux affords [(PPh3)2Pt(h3-
CH2CHCH2)]OTf as expected, although the reaction is
much slower than that in toluene at reflux.
ð13Þ
ambient temperature. In contrast, reaction of 10 with
MeI in CH2Cl2 at reflux did not proceed cleanly, and
after 12 h gave ca. 3:1 unreacted 10 and 9, as well as
[Ph3PMe]ꢀ.
Acknowledgements
3.4. Reactions of [(PPh3)2Pt(h3-CH2C(OCH2CHÄ
CH2)CHPh]OTf (7OTf)
/
This study was supported in part by the National
Science Foundation and The Ohio State University.
Since allyl groups are readily transferred to metal
under a variety of conditions [23], it was of interest to
ascertain
whether
7OTf
would
react
with
(PPh3)2Pt(C2H4). When equimolar amounts of the
aforementioned complexes were combined in chloro-
form at room temperatue, clean conversion occurred
within 10 min to afford 10 and [(PPh3)2Pt(h3-
CH2CHCH2)]ꢀ, characterized by 1H- and 31P{1H}-
NMR spectroscopy. This reaction probably proceeds
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/