Regioselective addition of secondary phosphine oxides to 3-(trialkylsilyl)- and 3-(trialkylgermyl)-2-propynals

Article abstract of DOI:10.1016/S0022-328X(02)01724-2

3-(Trialkylsilyl)- and 3-(trialkylgermyl)-2-propynals as well as 2-propynal react with secondary phosphine oxides by carbonyl group under mild conditions ( - 10 to 22 C) to give corresponding tertiary phosphine oxides with acetylenic and hydroxyl moieties

Full text of DOI:10.1016/S0022-328X(02)01724-2

Journal of Organometallic Chemistry 659 (2002) 172Á175
/
www.elsevier.com/locate/jorganchem
Regioselective addition of secondary phosphine oxides to
3-(trialkylsilyl)- and 3-(trialkylgermyl)-2-propynals
Nina K. Gusarova *, Aelita M. Reutskaya, Nina I. Ivanova, Alevtina S. Medvedeva,
Maria M. Demina, Peter S. Novopashin, Andrei V. Afonin, Alexander I. Albanov,
Boris A. Trofimov
Institute of Chemistry, Russian Academy of Sciences, Siberian Branch, 1 Favorsky Street, 664033 Irkutsk, Russia
Received 14 September 2001; received in revised form 8 July 2002; accepted 8 July 2002
Abstract
3-(Trialkylsilyl)- and 3-(trialkylgermyl)-2-propynals as well as 2-propynal react with secondary phosphine oxides by carbonyl
group under mild conditions (ꢀ
in quantitative yield. The reactivity of the aldehydes in this reaction drops in the following order: HCÅ
CC(O)HꢀEt3GeCÅCC(O)H. # 2002 Elsevier Science B.V. All rights reserved.
/
10 to 22 8C) to give corresponding tertiary phosphine oxides with acetylenic and hydroxyl moieties
/
CC(O)HꢀMe3SiCÅ
/
/
/
/
Keywords: 3-(Trimethylsilyl)-2-propynal; 3-(Triethylgermyl)-2-propynal; Secondary phosphine oxides; Nucleophilic addition; Competitive reactions;
1-(Diorganylphosphoryl)-3-[trialkylsilyl(or germyl)]-2-propyn-1-ols
1. Introduction
phenethyl)- and bis[2-(2-pyridyl)ethyl]phosphine oxides
(3, 4) [12] as an example, the data on the reaction of
acetylenic aldehydes with secondary phosphine oxides
are presented for the first time.
Reaction of a,b-acetylenic aldehydes with nucleophi-
lic reagents (e.g. amines, thiols, etc.) follows the scheme
of 1,4-addition to afford the corresponding Michael
adducts [1,2] or products of their subsequent cyclization
[3,4]. 3-(Trialkylsilyl)- and 3-(trialkylgermyl)-2-propy-
nals react with NH- and SH-acids as ambident electro-
philes with participation of carbonyl group and (or)
acetylenic moiety depending on both reaction conditions
and the nature of heteroatom in the initial reagents [5].
At the same time there is no data on the reactivity of
PH-acids in this reaction, although it would contribute
to the theoretical aspects of chemistry of element
substituted acetylenic aldehydes and lead to new con-
venient routes to the synthesis of new polyfunctional Si-,
Ge- and P-containing compounds, prospective polyden-
tate amphiphilic ligands for design of new metal
2. Results and discussion
2.1. Synthesis
Secondary phosphine oxides 3, 4 readily add to
propynals 1, 2 under mild conditions (ꢀ
THF or methanol) regioselectively at CÄO group to give
tertiary phosphine oxides 5Á7 in almost quantitative
yield.
The asymmetric carbon atom in phosphine oxides 5Á
/
10 to 22 8C,
/
/
/
complex catalysts (including the chiral ones) [6Á11]. In
the present paper, taking available 3-(trimethylsilyl)-
and 3-(triethylgermyl)-2-propynals (1, 2) [5] and bis(2-
/
7 gives rise to non-equivalence of signals of carbon
atoms in phenethyl and pyridylethyl groups. Moreover,
in 1H-NMR spectrum of compound 7 the signals of
protons in pyridylethyl groups are also non-equivalent.
2-Propynal 8 reacts with phosphine oxide 3 in the
same way to form 1-(diphenethylphosphoryl)-2-propyn-
1-ol (9).
* Corresponding author. Tel.:
396046
E-mail address: gusarova@irioch.irk.ru (N.K. Gusarova).
ꢁ
/
7-3952-466436; fax:
ꢁ7-3952-
/
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 7 2 4 - 2

N.K. Gusarova et al. / Journal of Organometallic Chemistry 659 (2002) 172Á
/175
173
2.2. Reactivity
effect of trimethylsilylethynyl group as compared with
triethylgermylethynyl group. As a result, transition state
A in the case of propynal 1 is more stable.
The reactivity of propynals 1 and 2 towards phos-
phine oxide 3 was evaluated using the method of
competitive reactions. According to the literature data
[5], the basicities of triethylgermylpropynal is higher
than that of triethylsilylpropynal. At the same time the
basicities of trimethyl- and triethylsilylpropynals are
comparable [5].
The dynamics of conversion of aldehydes 1, 2 and
formation of the corresponding phosphine oxides 5, 6
was monitored by the 1H-NMR spectra. For this
purpose, a THF solution of propynals 1, 2 and
phosphine oxide 3 in 1:1:2.2 molar ratio, respectively,
was used; the reaction was carried out in an NMR tube
at room temperature.
In order to qualitatively estimate the relative reactiv-
ity of propynal 8, an experiment was carried out in an
NMR tube for a mixture of propynals 8 and 1, in the
reaction with phosphine oxide 3. Comparison and
1
analysis of the H- and 31P-NMR spectra have shown
The process of formation of hydroxyphosphine oxides
5, 6 in the reaction mixture was resulting in an increase
of the intensity of trimethylsilyl protons (0.10 ppm, s)
for 5 and CH2-protons of triethylgermyl group (0.81
ppm, s) in the case of 6. The intensities of the
corresponding peaks of protons from propynals 1
(0.20 ppm, s) and 2 (0.94 ppm, q) have been synchro-
nously decreasing.
that the rate of the formation of phosphine oxide 9 is
higher than that for phosphine oxide 5. Thus, 10 min
after mixing the reagents 1, 3, 8 in THF at ꢀ10 8C, the
/
signal at dP 49.42 ppm resultant from phosphine oxide 9
was first to appear whereas the signals of protons of
phosphine oxide 5 in the 1H-NMR spectrum were
absent.
The data obtained prove that in the reaction with
phosphine oxide 3 trimethylsilylpropynal 1 is more
active than triethylgermylpropynal 2. Thus, in the first
10 min of the reaction the concentration of formed
phosphine oxide 5 is almost three times higher than that
of phosphine oxide 6. After 20 min this ratio decreases
to 2 and after 40 min to 1.5. Then the formation rates
for compounds 5 and 6 become relatively equal and
after 3.5 h the ratio of trimethylsilyl (5) and triethylger-
myl (6) products reaches 1.2. Relative rate constants for
the formation of hydroxyphosphine oxides 5 and 6
become 10.7 and 4.1 mol l minꢀ1, respectively. A higher
reactivity of trimethylsilylpropynal 1 in the studied
reaction is caused by a stronger electron withdrawing
3. Conclusions
Reaction of acetylenic aldehydes with secondary
phosphine oxides represents a new convenient approach
for the synthesis of previously unknown polyfunctional
chiral tertiary phosphine oxides. The reactivity of the
ambident electrophiles 1, 2, 8 in this process follows the
order: HCÅ
/
CC(O)Hꢀ
/
Me3SiCÅ
/
CC(O)Hꢀ
/
Et3GeCÅ
/
CC(O)H, which is in accordance with the literature
data on the activity of these aldehydes towards the N-
and S-nucleophiles [5].

174
N.K. Gusarova et al. / Journal of Organometallic Chemistry 659 (2002) 172Á175
/
4. Experimental
88Á90 8C (hexane). Anal. Calc. for C25H35GeO2P: C,
/
63.73; H, 7.49; Ge, 15.41; P, 6.57. Found: C, 63.80; H,
7.50; Ge, 15.25; P, 6.03%. 1H-NMR (250 MHz, CDCl3):
0.92 (m, 6H, 3CH2), 1.12 (m, 9H, 3CH3), 2.20 (m, 4H,
4.1. General
1
The H-, 13C- and 31P-NMR spectra were taken on
2PCH2), 3.03 (m, 4H, 2PhCH2), 4.91 (d, 2JPH
ꢂ10.7 Hz,
/
Bruker DPX 400 and DPX 250 spectrometers in CDCl3
solutions; HMDS as an internal standard, 85% H3PO4
as an external one, respectively. All chemical shifts are
presented relative to HMDS. In 13C-NMR spectra of
1H, CH), 6.15 (br s, 1H, OH), 7.32 (m, 10H, 2Ph).
13C{1H}-NMR (250 MHz, CDCl3): d 5.86 (s, GeCH2),
1
9.29 (s, CH3), 27.32; 28.36 (d, JPC
ꢂ60.0 Hz, PCH2),
/
2
1
27.76 (d, JPC
Hz, CH), 92.64 (d, JPC
101.49 (s, CHÃC Å), 126.48; 126.64 (s, Cp, Ph), 128.27 (s,
Co, Ph), 128.73; 128.80 (s, Cm, Ph), 141.06; 141.46 (d,
3JPC 13.3 Hz, Ci, Ph).31P-NMR (400 MHz, CDCl3): d
49.18 (s). IR (KBr, cmꢀ1): 3118Á
3018 (OH), 2165 (CÅ
C), 1147 (PÄO), 1202, 700, 580 (GeÃC).
ꢂ
/
4.0 Hz, PhCH2), 61.92 (d, JPC
ꢂ/77.2
3
compounds 5Á
/
7 (the signals were attributed using 2D
(1H and 13C) experiment techniques HSQC [13] and
HMBC [14]) the signals of two quarternary carbon
ꢂ
/
7.8 Hz, Å
/
C Ã
/
Ge(C2H5)3),
/
/
atoms of the CÅ
/
C fragment appear at 90Á/100 ppm
ꢂ
/
region. IR spectra were recorded on a Bruker IFS 25
instrument in KBr pellets and in thin film. Investigation
of the formation dynamics for hydroxyphosphine oxides
5, 6 was performed using a 3% molar solutions of
aldehydes 1, 2 and phosphine oxide 3 in THF (molar
/
/
/
/
4.4. 1-bis[2-(2-Pyridinyl)ethyl]phosphoryl-3-
(trimethylsilyl)-2-propyn-1-ol (7)
ratio 1:2:3ꢂ
mixed and placed in an NMR tube at ꢀ
/
1:1:2.2) were used. These solutions were
1
/
15 8C. H-
NMR spectra were recorded at a temperature of 22 8C
(proton chemical shifts were registered relative to THF).
Obtained analogously to 5 from 0.18 g (0.69 mmol) of
phosphine oxide 4 and 0.09 g (0.69 mmol) of 3-
(trimethylsilyl)-2-propynal in 2 ml of methanol at a
temperature of 22 8C (10 h). Yield 98%, viscous liquid.
Anal. Calc. for C20H27N2O2PSi: C, 62.15; H, 7.04; N,
7.25; P, 8.01; Si, 7.27. Found: C, 62.21; H, 7.07; N, 7.24;
P, 7.98; Si, 7.22%. 1H-NMR (250 MHz, CDCl3): 0.12 (s,
9H, 3CH3), 2.30; 2.36 (m, 4H, 2PCH2), 3.18; 3.31 (m,
4.2. 1-(Diphenethylphosphoryl)-3-(trimethylsilyl)-2-
propyn-1-ol (5)
To a solution of 0.20 g (0.77 mmol) of phosphine
oxide 3 in 1 ml of THF, a solution of 0.10 g (0.77 mmol)
of 3-(trimethylsilyl)-2-propynal in 1 ml of THF was
4H, 2CH2), 3.82 (br s, 1H, OH), 4.69 (d, 2JPH
1H, CH), 7.11 (m, 2H, H5ÃPy), 7.23 (m, 2H, H3Ã
7.61 (m, 2H, H4ÃPy), 8.48 (m, 2H, H6Ã
Py). 13C{1H}-
ꢂ/10.8 Hz,
added during 10 min at ꢀ10 8C. After removal of
/
/
/Py),
cooling, the solution was stirred at room temperature
(r.t.) for 1 h and 20 min. THF was removed in vacuum,
the residue was washed with ether. Yield 98%, m.p.
/
/
NMR (250 MHz, CDCl3): ꢀ0.54 (s, Si(CH3)3), 23.67;
/
24.61 (d, 1JPC
4.2 Hz, PyCH2), 60.51 (d, JPC
ꢂ
/
64.8 Hz, PCH2), 28.43; 29.34 (d, 2JPC
ꢂ
/
124Á125 8C (hexane). Anal. Calc. for C22H29O2PSi: C,
/
1
ꢂ/76.9 Hz, CH), 94.43
68.72; H, 7.60; P, 8.05; Si 7.30. Found: C, 68.63; H, 7.41;
3
(d, JPC
121.76; 121.97 (s, C5Ã
136.99; 137.39 (s, C4Ã
ꢂ
/
6.9 Hz, Å
/
C Ã
Py), 123.17; 123.58 (s, C3Ã
Py), 148.70; 149.05 (s, C6Ã
160.08; 160.24 (d, JPC
13.0 Hz, C2Ã
(400 MHz, CDCl3): d 49.27 (s). IR (film, cmꢀ1): 3175Á
3010 (OH), 2169 (CÅC), 1150 (PÄO), 1250, 846, 762
(SiÃC).
/
Si(CH3)3), 100.26 (s, CHÃ
/
C Å
/),
1
P, 7.94; Si, 7.02%. H-NMR (250 MHz, CDCl3): d 0.23
(s, 9H, 3CH3), 2.23 (m, 4H, 2PCH2), 3.04 (m, 4H,
/
/
Py),
/
/Py),
2
2PhCH2), 4.85 (d, JPH
ꢂ10.2 Hz, 1H, CH), 5.82 (br s,
/
3
ꢂ
/
/
Py). 31P-NMR
1H, OH), 7.32 (m, 10H, 2Ph). 13C{1H}-NMR (250
MHz, CDCl3): d 0.26 (s, Si(CH3)3), 26.28; 27.90 (d,
/
/
/
1JPC
ꢂ
/
60.0 Hz, PCH2), 27.60 (d, JPC
ꢂ4.1 Hz,
/
2
/
1
PhCH2), 61.70 (d, JPC
3JPC
6.9 Hz, ÅC ÃSi(CH3)3), 100.77 (s, CHÃ
126.44; 126.59 (s, Cp, Ph), 128.17 (s, Co, Ph), 128.69;
128.76 (s, Cm, Ph), 140.89; 141.24 (d, 3JPC
13.3 Hz, Ci,
Ph).31P-NMR (400 MHz, CDCl3): d 48.70 (s). IR (KBr,
cmꢀ1): 3108Á
3027 (OH), 2172 (CÅC), 1149 (PÄO),
1250, 842, 757 (SiÃC).
ꢂ
/
77.2 Hz, CH), 94.76 (d,
ꢂ
/
/
/
/
C Å),
/
ꢂ
/
4.5. 1-(Diphenethylphosphoryl)-2-propyn-1-ol (9)
/
/
/
Obtained analogously from 0.10 g (0.39 mmol) of
phosphine oxide 3 (in 1 ml of THF) and 0.05 g (0.9
/
mmol) of 2-propynal (in 1.5 ml of THF) at ꢀ10 to
/
4.3. 1-(Diphenethylphosphoryl)-3-(triethylgermyl)-2-
propyn-1-ol (6)
22 8C during 30 min. Yield 100%, viscous liquid of
dark-red color. Anal. Calc. for C19H21O2P: C, 73.06; H,
1
6.78; P, 9.92. Found: C, 73.16; H, 6.78; P, 9.95%. H-
NMR (400 MHz, CDCl3): 2.19 (m, 4H, 2PCH2), 2.61 (s,
Obtained analogously to 5 from 0.12 g (0.46 mmol) of
phosphine oxide 3 and 0.10 g (0.46 mmol) of 3-
(triethylgermyl)-2-propynal in 2 ml of THF at a
2
CH), 2.97 (m, 4H, 2PhCH2), 4.82 (d, JPH
1H, Å
/
ꢂ10.4
/
Hz, 1H, CH), 6.35 (br s, 1H, OH), 7.21 (m, 10H, 2Ph).
31P-NMR (400 MHz, CDCl3): d 49.42 (s).
temperature of ꢀ
/
10 to 22 8C (2.5 h). Yield 98%, m.p.

N.K. Gusarova et al. / Journal of Organometallic Chemistry 659 (2002) 172Á
/175
175
[8] Y. Li George, Angew. Chem. Int. Ed. 40 (2001) 1513.
References
[9] P. Braunstein, F. Naud, Angew. Chem. Int. Ed. 40 (2001) 681.
[10] T. Saito, T. Yokozawa, T. Ishizahi, T. Moroi, N. Sayo, T. Miura,
H. Kumobayashi, Adv. Synth. Catal. 343 (2001) 264.
[1] F. Wille, W. Schwab, Z. Naturforsch. B32 (1977) 733.
[2] A.V. Eremeev, D.A. Tikhomirov, E.E. Liepynsh, Khim. Geter-
otsikl. Soed. (1977) 207.
[11] M.A.O. Volland, B.F. Straub, I. Gruber, F. Rominger, P.
Hofmann, J. Organomet. Chem. 617Á618 (2001) 288.
/
[3] R. Kitzing, DE Pat. 2309525, Chem. Abstr. 79 (1973) 141521.
[4] A.S. Medvedeva, L.P. Saphronova, I.D. Kalikhman, M.G.
Voronkov, Izv. Akad. Nauk USSR Ser. Khim. (1976) 1799.
[5] A.S. Medvedeva, Zh. Org. Khim. 32 (1996) 289.
[6] S. Mecking, Angew. Chem. Int. Ed. 40 (2001) 534.
[7] Y.Li George, P.J. Fagan, P.L. Watson, Angew. Chem. Int. Ed. 40
(2001) 1106.
[12] N.K. Gusarova, S.F. Malysheva, S.N. Arbuzova, B.A. Trofimov,
Izv. Akad. Nauk Ser. Khim. (1998) 1695.
[13] G. Bodenhausen, D. Ruben, J. Chem. Phys. Lett. 69 (1980)
185.
[14] A. Bax, M.F. Summers, J. Chem. Soc. 108 (1986) 2093.