Asymmetric hydrosilylation of ketones
1053
33.4, 24.7 ppm; IR (KBr): vꢀ = 3,430, 2,920, 2,852, 2,826,
1,633, 1,610, 1,528, 1,370, 1,181, 807 cm-1; HR-EI-MS
(m/z): [M]? calcd for C24H36N4 380.5694, found 380.5701.
purified by column chromatography on silica gel with
hexane–EtOAc (10:1) as eluent.
General procedure for Zn(diamine)(diol)]-catalyzed
hydrosilylation of 4-methylacetophenone
(2R,3R,16R,17R,30R,31R)-1,4,15,18,29,32-Hexaaza-
(2,3:16,17:30,31)-tributano-(8,11:22,25:36,39)-trietheno-
1,2,3,4,5,14,15,16,17,18,19,28,29,30,31,32,33,42-
octadecahydro[42]annulene (L19, C54H72N6)
In a 5-cm3 round-bottomed flask 12.5 mm3 ZnEt2 (1 M in
hexane, 0.0125 mmol), the appropriate chiral ligand
(0.0125 mmol), and the diol (0.0125 mmol) were dissolved
in 1.5 cm3 freshly distilled toluene and stirred under an
argon atmosphere for 30 min. 4-Methylacetophenone
(0.344 mmol) and silane (0.413 mmol) were then added to
the mixture. The resulting solution was stirred at room
temperature for 24 h, then 1 cm3 NaOH (1 M in MeOH)
was added with vigorous stirring. The reaction mixture was
stirred for an additional hour at room temperature and the
solvents were then evaporated. The residue was dissolved
in a mixture of 10 cm3 H2O and 1 cm3 10 % HCl and
extracted with diethyl ether (3 9 10 cm3). The combined
organic extracts were washed with saturated aqueous
NaHCO3 solution, H2O, and brine, dried over anhydrous
MgSO4, and concentrated under vacuum. The product was
purified by column chromatography on silica gel with
hexane–EtOAc (10:1) as eluent.
Yield 84 %; white solid: m.p.:[320 °C (dichloromethane–
1
hexane); H NMR (300 MHz, CDCl3): d = 7.25 (s, 6H),
6.53 (d, J = 15.2 Hz, 6H), 6.22–6.16 (m, 6H), 3.29–3.25
(m, 6H), 3.19–3.15 (m, 6H), 2.55–2.49 (m, 6H), 1.72 (s,
6H), 1.69–1.61 (m, 6H), 1.52–1.45 (m, 6H), 1.44–1.34 (m,
12H) ppm; 13C NMR (126 MHz, CDCl3): d = 136.3,
130.5, 128.8, 126.4, 126.1, 61.1, 49.1, 49.0, 31.4,
25.0 ppm; IR (KBr): vꢀ = 3,424, 3,296, 2,928, 2,854,
2,370, 1,757, 1,450, 1,238, 1,120, 1,050, 964, 750 cm-1
HR-EI-MS (m/z): [M]? calcd for C54H72N6 805.1897,
found 805.1905.
;
(2R,3R,11R,12R,20R,21R)-1,4,10,13,19,22-Hexaaza-
(2,3:11,12:20,21)-tris(tetramethylene)-7,16,25-trihydroxy-
(6,8:15,17:24,26)-tris(2-tert-butyl-1-propen-3-yl)-
1,2,3,4,5,9,10,11,12,13,14,18,19,20,21,22,23,27-
octadecahydro[27]annulene (L20, C54H84N6O3)
Yield 93 %; glass; 1H NMR (400 MHz, CDCl3): d = 7.09
(s, 6H), 5.05 (s, 3H), 3.81 (m, 12H), 2.53–2.51 (m, 6H),
1.96 (s, 6H), 1.69–1.61 (m, 6H), 1.53–1.45 (m, 6H),
1.44–1.34 (m, 39H) ppm; 13C NMR (75 MHz, CDCl3):
d = 154.5, 154.0, 140.8, 125.0, 123.9, 60.3, 48.8, 48.2,
33.8, 31.6, 31.4, 30.8, 24.8 ppm; IR (KBr): vꢀ = 3,269,
2,950, 2,858, 1,609, 1,484, 1,362, 1,215 cm-1; HR-EI-MS
(m/z): [M]? calcd for C54H84N6O3 865.6605, found
865.6596.
Acknowledgments We are grateful to the Ministry of Science and
Higher Education (Poland) for financial support (grant no. PBZ-KBN-
NN204 555 939).
Open Access This article is distributed under the terms of the
Creative Commons Attribution License which permits any use, dis-
tribution, and reproduction in any medium, provided the original
author(s) and the source are credited.
General procedure for Zn(diamine)]-catalyzed
hydrosilylation of ketones
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