Compound 9a
(E)-6-((8R,9S,10R,13S,14S,17S)-17-((tert-butyldimethylsilyl)oxy)-13-methyl-2,3,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-3-methylhex-2-enenitrile
From: E- and Z-, di- and tri-substituted alkenyl nitriles through catalytic cross-metathesis
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Compound data: 1H NMR
Compound data: 13C NMR
Compound data: Crystallographic data
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
Following the general procedure outlined for compound 2a, a solution of Mo-2b in benzene (0.1 M, 25 μL, 2.5 μmol) and B(C6F5)3 in benzene (0.1 M, 75 μL, 7.5 μmol) were transferred by syringe to an oven-dried vial containing tert-butyldimethyl(((8R,9S,10R,13S,14S,17S)-13-methyl-17-((E)-4-methylhex-4-en-1-yl)-2,3,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)oxy)silane (23.5 mg, 0.050 mmol) and maleonitrile (5.9 mg, 0.075 mmol) in 0.15 mL benzene. The resulting solution was allowed to stir for 4 h at 40 °C. The reaction was quenched by the addition of wet CDCl3 and analysis of the unpurified mixture revealed 67% consumption of tert-butyldimethyl(((8R,9S,10R,13S,14S,17S)-13-methyl-17-((E)-4-methylhex-4-en-1-yl)-2,3,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)oxy)silane. The resulting red oil was purified by silica gel chromatography (2% to 5% Et2O in hexanes) to afford a 16.9 mg mixture of inseparable 9a in 92:8 E:Z ratio (15.9 mg, 0.0330 mmol, 66% yield) and aryloxide ligand 2,2'',4,4'',6,6''-hexaisopropyl-[1,1':3',1''-terphenyl]-2'-ol (1.0 mg, 0.00200 mmol, 4.0% yield) as off-white solid. M.p.: 150–152 oC; IR (neat): 2983 (w), 2949 (m), 2930 (s), 2908 (m), 2853 (m), 2832 (w), 2213 (w), 1471 (w), 1256 (m), 1129 (w), 1092 (w), 1072 (s), 903 (w), 832 (s), 802 (m), 774 (m); 1H NMR (600 MHz, CDCl3): 9a: E isomer (major): δ 5.38 (1H, s), 5.10 (1H, s), 2.22–2.11 (3H, m), 2.05 (3H, s), 2.03–1.94 (2H, m), 1.91 (2H, d, J = 5.5 Hz), 1.84–1.72 (4H, m), 1.71–1.63 (2H, m), 1.62–1.49 (3H, m), 1.46 (1H, d, J = 12.2 Hz), 1.40–1.21 (6H, m), 1.21–1.15 (1H, m), 1.10 (3H, ddd, J = 22.7, 12.0, 6.4 Hz), 0.87 (9H, s), 0.82 (3H, s), 0.61 (1H, qd, J = 10.9, 4.1 Hz), 0.07 (6H, d, J = 21.3 Hz); aryloxide ligand (resolved signals only): δ 7.12–6.95 (7H, m), 4.52 (1H, s), 3.48 (1H, q, J = 7.0 Hz), 2.94 (2H, p, J = 6.9 Hz), 2.72 (4H, p, J = 6.8 Hz); 13C NMR (100 MHz, CDCl3): 10a: δ 165.7, 140.6, 120.0, 117.5, 95.1, 86.4, 50.5, 48.8, 48.0, 42.2, 42.1, 39.7, 38.4, 35.7, 34.7, 32.2, 32.1, 29.0, 26.3, 26.2, 25.7, 23.8, 22.7, 22.3, 21.2, 18.8, 15.67, -1.41; HRMS [M+H]+ calcd for C31H52NOSi: 482.3818, found: 482.3821.
