Academician A. N. NESMEYANOV, K. N. ANISIMOV, N. E. KOLOBOVA,
I. B. ZLOTINA

REDUCTION OF KETONES OF CYCLOPENTADIENYLMANGANESE TRICARBONYL AND DEHYDRATION OF SECONDARY ALCOHOLS

In a previous communication it was described that acetylcyclopentadienylmanganese tricarbonyl reacts normally with the Grignard reagent and with Iotsich’s “complex,” forming tertiary alcohols, and, in the second case, acetylene alcohols \((^1)\).

In the present work we describe the reduction of ketones of cyclopentadienylmanganese tricarbonyl with lithium aluminum hydride, with and without aluminum trichloride, to the corresponding alcohols and alkyl-(aralkyl)-cyclopentadienylmanganese tricarbonyls \((^2, ^3)\). We also describe the dehydration of the secondary alcohols obtained with potassium bisulfate and sulfuric acid to alkenylcyclopentadienylmanganese tricarbonyls and an ether:

\[ (\mathrm{CO})_3\mathrm{MnC}_5\mathrm{H}_4-\mathrm{CH}-\mathrm{O}-\mathrm{CH}-\mathrm{C}_5\mathrm{H}_4\mathrm{Mn}(\mathrm{CO})_3 \]
\[ \phantom{(\mathrm{CO})_3\mathrm{MnC}_5\mathrm{H}_4-}\big| \qquad\qquad \big| \]
\[ \phantom{(\mathrm{CO})_3\mathrm{MnC}_5\mathrm{H}_4-}\mathrm{CH}_3 \qquad\quad \mathrm{CH}_3 \]

The structure of the compounds presented here is confirmed by the IR spectrum*. The spectrum of each of these compounds contains vibration frequencies characteristic of the principal groups of atoms composing the molecules of cyclopentadienylmetal carbonyls and their derivatives \((^{4-7})\)

\[ \mathrm{CH}\ —\ 3120—3105\ \mathrm{cm}^{-1}; \]
\[ \mathrm{Me}(\mathrm{CO})_3\ —\ 2060—2019\ \mathrm{cm}^{-1};\quad 1967—1908\ \mathrm{cm}^{-1}; \]
\[ \mathrm{Me}=\mathrm{V},\ \mathrm{Mn},\ \mathrm{Fe},\ \mathrm{CO}. \]

In addition to these general vibration frequencies, there are characteristic vibration frequencies of the introduced functional groups, which are given in boldface.

Experimental Part

1-Oxyethyl-1-cyclopentadienylmanganese tricarbonyl. In a 5-necked flask of volume 0.5 liter, fitted with a stirrer, reflux condenser, dropping funnel, and nitrogen inlet**, there was dissolved under nitrogen 10 g (0.0407 mole) of acetylcyclopentadienylmanganese tricarbonyl in 100 ml of absolute ether. Then, over the course of 0.5 hour, a suspension of 0.75 g (0.0203 mole) of \(\mathrm{LiAlH}_4\) in 100 ml of absolute ether was added. After heating for 2 hours, the reaction mixture was cooled and decomposed with 50 ml of absolute ethyl acetate and a concentrated solution of \(\mathrm{NH}_4\mathrm{Cl}\). After filtration, the ether layer was dried over \(\mathrm{Na}_2\mathrm{SO}_4\), and then the solvent was removed. Distillation in vacuo at \(55—56^\circ\) \((5 \cdot 10^{-3}\ \mathrm{mm})\) gave 7.2 g (71%) of a light-yellow viscous oil; \(n_D^{20}\ 1.5940;\ d_4^{20}\ 1.4347\).

\[ \begin{aligned} &\text{Found, \%: } &&\mathrm{C}\ 48.39,\ 48.55;\ \mathrm{H}\ 3.66;\ 3.69;\ \mathrm{Mn}\ 22.02;\ 22.26\\ &\mathrm{C}_{10}\mathrm{H}_9\mathrm{O}_4\mathrm{Mn}. \quad \text{Calculated, \%: } &&\mathrm{C}\ 48.38;\ \mathrm{H}\ 3.62;\ \mathrm{Mn}\ 22.09 \end{aligned} \]

IR spectrum \((\nu,\ \mathrm{cm}^{-1})\)***: 580 (s.), 635 (s.), 670 (s.), 840 (av.), 876 (av.), 930 (av.), 1011 (av.), 1037 (av.), 1050 (av.), 1080 (av.), 1100 (av.), 1246 (w.), 1270 (w.), 1322 (w.), 1380 (av.), 1416 (av.), 1460 (av.), 1935 (s.), 2030 (s.), 2880 (w.) 2940 (w.), 2990 (av.), 3130 (w.), 3400 (s.), 3610 (av.).

* Measurement of the IR spectra was carried out by Yu. N. Sheinker and G. G. Dvoryantseva, to whom the authors express their gratitude.
** The apparatus described was used in all subsequent experiments.
*** s.—strong intensity; av.—average intensity; w.—weak intensity.

1-Oxypropyl-1-cyclopentadienylmanganese tricarbonyl. To 15 g (0.0577 mole) of propionylcyclopentadienylmanganese tricarbonyl, dissolved in 125 ml of abs. ether, over the course of 0.5 hr was added a suspension of 1.07 g (0.0282 mole) of LiAlH₄ in 125 ml of abs. ether. After heating for 2 hr, the reaction mixture was cooled and worked up as in the preceding experiment. Vacuum distillation at 69–70°/6·10⁻³ mm gave 11 g (73%) of a yellow viscous oil; \(n_D^{20}\) 1.5823; \(d_4^{20}\) 1.3773.

Found, %: C 50.64; 50.73; H 4.40, 4.47; Mn 20.17; 20.08
\(\mathrm{C_{11}H_{11}O_4Mn}\). Calculated, %: C 50.38; H 4.19; Mn 20.99

IR spectrum (\(\nu\), cm⁻¹): 500 (medium), 540 (strong), 635 (strong), 670 (strong), 740 (weak), 792 (weak), 840 (strong), 855 (strong), 882 (medium), 911 (medium), 938 (medium), 976 (strong), 1040 (strong), 1092 (strong), 1240 (medium), 1382 (medium), 1416 (medium), 1465 (medium), 1932 (strong), 2022 (strong), 2890 (medium), 2950 (strong), 2985 (strong), 3125 (medium), 3450 (strong), 3620 (medium).

Phenyl-oxymethylcyclopentadienylmanganese tricarbonyl. To 10 g (0.0325 mole) of benzoylcyclopentadienylmanganese tricarbonyl, dissolved in 100 ml of abs. ether, over the course of 0.5 hr was added a suspension of 0.6 g (0.0160 mole) of LiAlH₄ in 100 ml of abs. ether. After heating for 2 hr, the reaction mixture was cooled and worked up as indicated above. 8.55 g (85%) of yellow crystals with m.p. 82–83° (from petroleum ether) were obtained.

Found, %: C 58.42; 58.47; H 3.69; 3.64
\(\mathrm{C_{15}H_{11}O_4Mn}\). Calculated, %: C 58.06; H 3.54

IR spectrum (\(\nu\), cm⁻¹) (crystals in petroleum jelly): 435 (weak), 580 (strong), 636 (strong), 655 (strong), 707 (strong), 740 (strong), 791 (weak), 830 (weak), 845 (strong), 918 (medium), 933 (medium), 1000 (strong), 1031 (medium), 1042 (medium), 1082 (medium), 1197 (weak), 1255 (strong), 1307 (strong), 1335 (medium), 1380 (medium), 1407 (strong), 1430 (strong), 1460 (strong), 1502 (medium), 1920 (strong), 1942 (strong), 2020 (strong), 2865 (strong), 2880 (strong), 2925 (strong), 2960 (strong), 3045 (medium), 3080 (medium), 3130 (strong), 3450 (strong).

Ethylcyclopentadienylmanganese tricarbonyl. Into abs. ether (20 ml), under nitrogen, were introduced 5.44 g (0.0407 mole) of AlCl₃, and after cooling, a suspension of 1.54 g (0.0407 mole) of LiAlH₄ in 100 ml of abs. ether was added. Then, at room temperature and with vigorous stirring, over the course of 0.5 hr, 10 g (0.0407 mole) of acetylcyclopentadienylmanganese tricarbonyl in 50 ml of abs. ether was added. After 15 min the reaction mixture was decomposed with ice water, and the ether layer was washed with NaHCO₃ solution and dried over Na₂SO₄. After removal of the ether, vacuum distillation (34–35°/2·10⁻² mm) gave 6.8 g (72%) of a light-yellow oil; \(n_D^{20}\) 1.5784; \(d_4^{20}\) 1.3358. Literature data (⁸): \(n_D^{20}\) 1.5760, \(d_4^{20}\) 1.3298.

Found, %: C 51.67; 51.97; H 3.94; 3.95
\(\mathrm{C_{10}H_9MnO_3}\). Calculated, %: C 51.72; H 3.88

IR spectrum (\(\nu\), cm⁻¹): 540 (strong), 635 (strong), 668 (strong), 790 (weak), 837 (medium), 910 (medium), 1028 (weak), 1050 (weak), 1212 (weak), 1270 (weak), 1323 (medium), 1370 (weak), 1384 (weak), 1412 (weak), 1447 (medium), 1465 (medium), 2489 (medium), 1930 (strong), 2025 (strong), 2880 (medium), 2950 (medium), 2980 (strong), 3125 (weak).

Propylcyclopentadienylmanganese tricarbonyl. To 5.86 g (0.0438 mole) of AlCl₃ in 30 ml of abs. ether saturated with nitrogen, with cooling, was added a suspension of 1.67 g (0.0438 mole) of LiAlH₄ in 100 ml of abs. ether. Then, at room temperature, over the course of 0.5 hr and with stirring, 11.4 g (0.0438 mole) of propionylcyclopentadienylmanganese tricarbonyl in 50 ml of abs. ether was introduced. After 15 min the reaction mixture was decomposed with ice water. After the usual work-up, vacuum distillation (51–52°/3·10⁻² mm) gave 7.3 g (68%) of a light-yellow oil; \(n_D^{20}\) 1.5681; \(d_4^{20}\) 1.2974.

Found, %: C 53.53; 53.40; H 4.62, 4.58; Mn 21.96, 22.12
\(\mathrm{C_{11}H_{11}MnO_3}\). Calculated, %: C 53.65; H 4.47; Mn 22.35

IR spectrum (\(\nu\), cm⁻¹): 540 (medium), 635 (strong), 720 (medium), 795 (weak), 838 (weak), 1033 (weak), 1053 (weak), 1093 (weak), 1382 (weak), 1415 (weak), 1468 (weak), 1487 (weak), 1928 (strong), 2022 (strong), 2885 (weak), 2945 (weak), 2975 (weak), 3120 (weak).

Benzylcyclopentadienylmanganese tricarbonyl. Under the conditions described above, benzylcyclopentadienylmanganese tricarbonyl was obtained from 4.34 g (0.0325 mole) of AlCl₃ in 20 ml of abs. ether, 1.23 g (0.0325 mole) of LiAlH₄ in 100 ml of abs. ether, and 10 g (0.0325 mole) of benzylcyclopentadienylmanganese tricarbonyl in 50 ml of abs. ether. After decomposition of the mixture with ice water, the ethereal layer was washed with a solution of NaHCO₃, dried over Na₂SO₄, and the ether was removed. The separated viscous mass was chromatographed on Al₂O₃ in heptane. On elution with a heptane–benzene mixture (1 : 1), 11 g (85%) of a yellow crystalline product was isolated, m.p. 37–38° (from petroleum ether at −70°).

Found, %: C 61.78, 61.47; H 3.82, 3.98; Mn 18.71, 18.33
C₁₅H₁₁MnO₃. Calculated, %: C 61.22; H 3.74; Mn 18.70

IR spectrum (ν, cm⁻¹) (crystals in Vaseline oil): 430 (w.), 470 (m.), 492 (w.), 500 (w.), 540 (s.), 565 (m.), 606 (w.), 630–640 (s.), 692 (s.), 713 (s.), 766 (s.), 835 (s.), 860 (m.), 888 (w.), 920 (m.), 936 (m.), 1028 (m.), 1048 (w.), 1066 (m.), 1072 (m.), 1371 (m.), 1383 (m.), 1411 (m.), 1441 (m.), 1457 (s.), 1480 (s.), 2497 (s.), 1586 (m.), 1602 (m.), 1903 (m.), 1940 (m.), 2020 (s.), 2860 (s.), 2925 (s.), 2965 (s.), 3035 (s.), 3080 (s.), 3100 (s.), 3120 (s.), 3135 (s.).

Vinylcyclopentadienylmanganese tricarbonyl. 4.7 g (0.0189 mole) of 1-hydroxyethyl-1-cyclopentadienylmanganese tricarbonyl ($n_D^{20}$ 1.5936), 0.4 g of KHSO₄, and a small amount of hydroquinone were heated in a sealed ampoule for 2 h at 200°. After opening the ampoule, 3.25 g (75%) of a light-yellow mobile liquid was isolated by distillation in vacuo at 29–30°/5 · 10⁻³ mm; $n_D^{20}$ 1.6080; $d_4^{20}$ 1.3807.

Found, %: C 52.04, 51.79; H 3.00, 3.16; Mn 23.09, 23.39
C₁₀H₇MnO₃. Calculated, %: C 52.17; H 3.04; Mn 23.91

IR spectrum (ν, cm⁻¹): 540 (s.), 635 (s.), 665 (s.), 730 (s.), 838–845 (s.), 922 (s.), 989 (s.), 1038 (s.), 1054 (s.), 1100 (m.), 1154 (w.), 1206 (m.), 1248 (m.), 1296 (m.), 1352 (m.), 1380 (s.), 1402 (s.), 1485 (s.), 1633 (s.), 1928 (s.), 2022 (s.), 3000 (m.), 3025 (m.), 3105 (s.), 3125 (s.).

On bromination of vinylcyclopentadienylmanganese tricarbonyl in a heptane–benzene mixture (1 : 1), a yellow crystalline product was isolated, m.p. 45–46° (from petroleum ether).

Found, %: C 31.27, 30.99; H 1.84, 1.64; Mn 14.08, 13.65; Br 41.47, 41.38
C₁₀H₇Br₂MnO₃. Calculated, %: C 30.76; H 1.79; Mn 14.10; Br 41.02

Propen-1-yl-1-cyclopentadienylmanganese tricarbonyl. 3.15 g (0.0120 mole) of 1-hydroxypropyl-1-cyclopentadienylmanganese tricarbonyl ($n_D^{20}$ 1.5823), 0.3 g of KHSO₄, and a small amount of hydroquinone were heated in a sealed ampoule for 1 h at 180°. After opening the ampoule, 2.52 g (86%) of a light-yellow mobile liquid was isolated by distillation in vacuo (51–52°/2 · 10⁻² mm); $n_D^{20}$ 1.6034; $d_4^{20}$ 1.3306.

Found, %: C 54.25, 54.04; H 3.80, 3.73; Mn 22.03, 22.20
C₁₁H₉MnO₃. Calculated, %: C 54.10; H 3.68; Mn 22.54

IR spectrum (ν, cm⁻¹): 540 (s.), 635 (s.), 669 (s.), 722 (s.), 758 (w.), 839 (s.), 916 (m.), 963 (s.), 1037 (m.), 1050 (m.), 1067 (w.), 1207 (w.), 1292 (w.), 1307 (w.), 1380 (m.), 1415 (w.), 1450 (m.), 1482 (m.), 1669 (m.), 1920 (s.), 2018 (s.), 2865 (m.), 2890 (m.), 2925 (m.), 2955 (s.), 2985 (m.), 3020 (m.), 3040 (m.), 3125 (w.).

1,1-Di-(cyclopentadienylmanganese tricarbonyl)ethyl ether. 1 g (0.0040 mole) of 1-hydroxyethyl-1-cyclopentadienylmanganese tricarbonyl ($n_D^{20}$ 1.5936) was treated with 45% H₂SO₄. The resulting viscous mass was washed with distilled water and dried in vacuo.

Recrystallization from petroleum ether gave 0.15 g (16%) of light-yellow crystals, m.p. 85–86°.

\[ \mathrm{C}_{20}\mathrm{H}_{16}\mathrm{O}_{7}\mathrm{Mn}_{2}. \]
Found, %: C 50.23, 50.11; H 3.50, 3.33; Mn 22.79, 22.73.
Calculated, %: C 50.20; H 3.34; Mn 23.01.

IR spectrum \((\nu,\ \mathrm{cm}^{-1})\) (crystals in Vaseline oil): 420 (medium), 475 (weak), 495 (medium), 505 (medium), 535 (strong), 555 (medium), 640 (strong), 670 (strong), 692 (strong), 830 (strong), 840 (strong), 853 (medium), 900 (medium), 918 (medium), 925 (medium), 1018 (medium), 1034 (medium), 1060 (strong), 1091 (strong), 1107 (strong), 1220 (weak), 1245 (medium), 1311 (strong), 1318 (strong), 1350 (medium), 1375 (strong), 1387 (medium), 1415 (medium), 1459 (strong), 1492 (medium), 1935 (strong), 2016 (strong), 2865 (strong), 2930 (strong), 2965 (strong), 3120 (medium).

Institute of Organoelement Compounds
of the Academy of Sciences of the USSR

Received
30 IX 1963

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