The Journal of Organic Chemistry
Article
136.99, 133.7, 130.2, 129.6, 128.6, 127.9, 121.6, 83.2, 83.1, 66.2, 24.7,
24.6.
CDCl3): δ 83.1, 82.6, 64.9, 31.9, 31.5, 29.6, 29.5, 29.3, 25.6, 24.5,
24.4, 22.7, 14.1.
4,4,5,5-Tetramethyl-2-phenethoxy-1,3,2-dioxaborolane (2o).11a
2-(Dodecyloxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2af).
Reaction time: 12 h. NMR yield: 99%. 1H NMR (400 MHz,
CDCl3): δ 3.80 (t, J = 6.5 Hz, 2H), 1.50−1.46 (m, 2H), 1.24 (s,
42H), 1.22 (s, 12H), 0.85 (t, J = 6.4 Hz, 3H). 13C NMR (101 MHz,
CDCl3): δ 83.2, 82.7, 65.1, 32.0, 31.5, 29.7, 29.6, 29.4, 25.7, 24.64,
24.60, 24.5, 22.8, 14.2. 11B NMR (161 MHz, CDCl3): δ 22.4
(−CH2OBpin), 21.3 ((Bpin)2O).
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NMR yield: >99%. H NMR (400 MHz, CDCl3): δ 7.27−7.15 (m,
5H), 4.03 (t, J = 6.7 Hz, 2H), 2.85 (t, J = 6.6 Hz, 2H), 1.24 (s, 24H),
1.16 (s, 12H). 13C NMR (101 MHz, CDCl3): δ 138.5, 129.2, 128.3,
126.3, 83.2, 82.7, 65.7, 38.1, 24.6.
4,4,5,5-Tetramethyl-2-(3-phenylpropoxy)-1,3,2-dioxaborolane
(2p).11a NMR yield: >99%. 1H NMR (400 MHz, CDCl3): δ 7.25 (t, J
= 6.9 Hz, 2H), 7.17 (d, J = 6.6 Hz, 3H), 3.85 (t, J = 5.7 Hz, 2H), 2.67
(t, J = 7.5 Hz, 2H), 1.90−1.83 (m, 2H), 1.24 (s, 36H). 13C NMR
(101 MHz, CDCl3): δ 141.9, 128.6, 128.4, 125.8, 83.2, 82.8, 64.2,
33.2, 31.9, 24.7, 24.6.
4,4,5,5-Tetramethyl-2-(tetradecyloxy)-1,3,2-dioxaborolane
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(2ag). Reaction time: 12 h. NMR yield: 99%. H NMR (500 MHz,
CDCl3): δ 3.82 (br, 2H), 1.56 (br, 2H), 1.26 (br, 58H), 0.88 (br,
3H). 11B NMR (161 MHz, CDCl3): δ 22.4 (−CH2OBpin), 21.3
((Bpin)2O).
2-(2,2-Diphenylethoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
(2q).11a NMR yield: >99%. H NMR (400 MHz, CDCl3): δ 7.28−
1
2-(Hexadecyloxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
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7.22 (m, 8H), 7.22−7.12 (m, 2H), 4.39 (d, J = 7.1 Hz, 2H), 4.22 (t, J
= 7.2 Hz, 1H), 1.26 (s, 24H), 1.13 (s, 12H). 13C NMR (101 MHz,
CDCl3): δ 141.9, 128.6, 128.5, 126.6, 83.3, 82.8, 67.9, 52.6, 24.6.
3-(2-((4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)oxy)ethyl)-
1H-indole (2r).11a NMR yield: 86%. 1H NMR (400 MHz, CDCl3): δ
7.99 (d, J = 8.0 Hz, 2H), 7.68 (d, J = 8.0 Hz, 1H), 7.62 (d, J = 7.6 Hz,
2H), 4.22 (t, J = 7.0 Hz, 7H), 3.06 (t, J = 6.9 Hz, 8H), 1.31 (s).
2-(Cyclobutylmethoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
(2t). NMR yield: >99%. 1H NMR (500 MHz, CDCl3): δ 3.78 (d, J =
6.3 Hz, 2H), 2.54−2.48 (m, 1H), 1.97 (d, J = 6.4 Hz, 2H), 1.86−1.72
(m, 4H), 1.25 (s, 24H), 1.23 (s, 12H). 13C NMR (126 MHz, CDCl3):
δ 83.3, 82.8, 68.9, 36.5, 24.6, 24.30, 18.4.
(2ah). Reaction time: 12 h. NMR yield: 99%. H NMR (400 MHz,
CDCl3): δ 3.82 (t, J = 6.6 Hz, 2H), 1.58−1.53 (m, 2H), 1.27 (s,
50H), 1.24−1.23 (m, 12H), 0.87 (t, J = 6.6 Hz, 3H).
4,4,5,5-Tetramethyl-2-(octadecyloxy)-1,3,2-dioxaborolane
(2ai).11b Reaction time: 12 h. NMR yield: 99%. 1H NMR (400 MHz,
CDCl3): δ 3.82 (t, J = 6.5 Hz, 2H), 1.56−1.52 (m, 2H), 1.27 (s,
24H), 1.25 (s, 42H), 0.88 (d, J = 6.2 Hz, 3H).
(Z)-4,4,5,5-Tetramethyl-2-(octadec-9-en-1-yloxy)-1,3,2-dioxa-
borolane (2aj).11b Reaction time: 12 h. NMR yield: 99%. H NMR
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(400 MHz, CDCl3): δ 5.32 (br, 2H), 3.81 (br, 2H), 1.99 (br, 4H),
1.54 (br, 2H), 1.25 (br, 59H), 0.86 (br, 3H). 13C NMR (101 MHz,
CDCl3): δ 129.9, 83.3, 82.7, 65.1, 32.0, 31.6, 29.9, 29.8, 29.7, 29.6.
29.4, 29.3, 27.3, 25.7, 25.6, 24.6, 22.8, 14.2.
2-((8Z,11Z)-Heptadeca-8,11-dien-1-yloxy)-4,4,5,5-tetramethyl-
1,3,2-dioxaborolane (2ak). Reaction time: 12 h. NMR yield: 88%.
1H NMR (400 MHz, CDCl3): δ 5.38−5.37 (m, 4H), 3.82 (t, 2H),
2.76 (t, 2H), 2.07−2.0 (m, 4H), 1.63−1.5 (m, 3H), 1.36−1.28 (m,
20H), 1.25 (br, 36H), 0.88 (t, 3H). 11B NMR (161 MHz, CDCl3): δ
22.4 (−CH2OBpin), 21.3 ((Bpin)2O).
(S)-2-(2-(6-Methoxynaphthalen-2-yl)propoxy)-4,4,5,5-tetrameth-
yl-1,3,2-dioxaborolane (2al). NMR yield: >99%. 1H NMR (400
MHz, CDCl3): δ 7.65 (dd, J = 8.5, 4.3 Hz, 2H), 7.58 (s, 1H), 7.33 (d,
J = 8.4 Hz, 1H), 7.11−7.06 (m, 2H), 4.03 (dd, J = 10.2, 6.5 Hz, 1H),
3.93 (dd, J = 10.2, 7.1 Hz, 1H), 3.87 (s, 3H), 3.10 (h, J = 6.9 Hz, 1H),
1.34 (d, J = 7.0 Hz, 3H), 1.25 (s, 24H), 1.12 (s, 12H). 13C NMR (101
MHz, CDCl3): δ 157.3, 138.9, 133.5, 129.2, 129.1, 126.8, 126.7,
125.7, 118.6, 105.6, 83.2, 82.7, 70.4, 55.3, 41.3, 24.6, 24.5, 17.7. 11B
NMR (161 MHz, CDCl3): δ 22.5 (−CH2OBpin), 21.3 ((Bpin)2O).
2-(2-(4-Isobutylphenyl)propoxy)-4,4,5,5-tetramethyl-1,3,2-dioxa-
borolane (2am). NMR yield: >99%. 1H NMR (400 MHz, CDCl3): δ
7.11 (br, 4H), 3.91 (br, 2H), 2.96 (br, 1H), 2.40 (br, 2H), 1.84 (br,
1H), 1.44 (br, 3H), 1.29 (s, 24H), 1.20 (s, 12H), 0.91 (br, 6H). 13C
NMR (101 MHz, CDCl3): δ 141.0, 139.7, 129.1, 127.3, 83.2, 82.7,
70.6, 45.2, 41.0, 30.3, 27.0, 24.6, 22.5, 17.7. 11B NMR (161 MHz,
CDCl3): δ 22.5 (−CH2OBpin), 21.3 ((Bpin)2O).
2-(Cyclopropylmethoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaboro-
lane (2u). NMR yield: 91%. 1H NMR (400 MHz, CDCl3): δ 3.64 (d,
J = 6.9 Hz, 2H), 1.39 (d, J = 4.5 Hz, 1H), 0.49−0.41 (m, 2H), 0.20
(q, J = 5.0 Hz, 2H). 13C NMR (101 MHz, CDCl3): δ 83.1, 83.0, 82.6,
69.3, 24.5, 12.3, 2.7.
4,4,5,5-Tetramethyl-2-(neopentyloxy)-1,3,2-dioxaborolane
(2v).11a NMR yield: >99%. H NMR (400 MHz, CDCl3): δ 3.50 (s,
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2H), 1.25 (s, 36H), 0.88 (s, 9H).
2-Ethoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2w):11a NMR
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yield: >99%. H NMR (400 MHz, CDCl3): δ 3.88 (q, J = 7.0 Hz,
1H), 1.24 (s, 36H), 1.20 (t, J = 6.9 Hz, 2H).
2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2x).22
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NMR yield: >99%. H NMR (500 MHz, CDCl3): δ 3.61 (s, 3H),
1.27 (s, 36H).
1,2-Bis((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)oxy)ethane
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(2y). NMR yield: >99%. H NMR (400 MHz, CDCl3): δ 3.85 (s,
4H), 1.18 (s, 48H). 13C NMR (101 MHz, CDCl3): δ 83.0, 82.7, 64.9,
24.4.
3-((4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)oxy)-
propanenitrile (2z). NMR yield: >99%. 1H NMR (400 MHz,
CDCl3): δ 4.04 (t, J = 6.0 Hz, 2H), 2.60 (t, J = 6.1 Hz, 2H), 1.24 (s,
48H). 13C NMR (101 MHz, CDCl3): δ 117.3, 83.6, 83.3, 59.9, 24.6,
20.5. 11B NMR (161 MHz, CDCl3): δ 22.5 (−CH2OBpin), 21.4
((Bpin)2O).
2-(((3R,8R,9S,10S,13R,14S,17R)-10,13-Dimethyl-17-((R)-5-
((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)oxy)pentan-2-yl)-
hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)oxy)-4,4,5,5-
tetramethyl-1,3,2-dioxaborolane (2an). NMR yield: >99%. 1H
NMR (400 MHz, CDCl3): δ 3.97−3.92 (m, 1H), 3.77−3.71(m,
2H), 1.93−1.91 (m, 1H), 1.85−1.79 (m, 4H), 1.64−1.56 (m, 2H),
1.45−1.36 (m, 8 H), 1.24 (s, 10 H), 1.22 (s, 24H), 1.13−0.94 (m,
6H), 0.87 (s, 3H), 0.60 (s, 3H). 13C NMR (101 MHz, CDCl3): δ
83.0, 82.5, 82.4, 74.2, 65.4, 56.4, 56.2, 42.6, 41.8, 40.2, 40.1, 35.8,
35.4, 35.1, 34.9, 34.4, 31.6, 29.1, 28.2, 28.0, 27.1, 26.3, 24.54, 24.5,
24.1, 23.3, 20.7, 18.5, 12.0. 11B NMR (161 MHz, CDCl3): δ 22.5
(−CH2OBpin), 21.3 ((Bpin)2O).
General Procedure for the Hydrolysis of 2. After completion
of the hydroboration reaction, the solvent and unreacted HBpin were
removed in a vacuum, and the resulted boronate ester residue was
hydrolyzed with silica gel (1 g)/methanol (5 mL) for 3−5 h at 60 °C.
An aliquot was then removed in a vacuum and the residue was
purified by column chromatography over silica gel (100−200 mesh)
with a hexane/ethyl acetate (8:2) mixture as eluent, which provided
the pure primary alcohol.
2-(3-Bromopropoxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
(2aa). NMR yield: >99%. 1H NMR (400 MHz, CDCl3): δ 3.95 (t, J =
5.7 Hz, 2H), 3.48 (t, J = 6.5 Hz, 2H), 2.10−2.04 (m, 2H), 1.24 (s,
36H). 13C NMR (101 MHz, CDCl3): δ 83.2, 83.0, 62.6, 34.4, 29.9,
24.6, 24.5. 11B NMR (161 MHz, CDCl3): δ 22.3 (−CH2OBpin), 21.3
((Bpin)2O).
2-(Hexyloxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2ab).9b
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NMR yield: >99%. H NMR (400 MHz, CDCl3): δ 3.82 (t, J = 6.5
Hz, 2H), 1.57−1.51 (m, 2H), 1.26 (s, 30H), 1.24 (s, 12H), 0.87 (t, J
= 6.2 Hz, 3H). 13C NMR (101 MHz, CDCl3): δ 83.3, 82.7, 65.1, 31.6,
31.5, 25.4, 24.7, 24.6, 22.7, 14.2.
1,6-Bis((4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)oxy)hexane
(2ac).11a NMR yield: >99%. 1H NMR (500 MHz, CDCl3): δ 3.82 (t,
J = 6.5 Hz, 4H), 1.58−1.53 (m, 4H), 1.37−1.32 (m, 4H), 1.27 (s,
48H), 1.24 (s, 24H). 13C NMR (126 MHz, CDCl3): δ 83.4, 82.8,
65.0, 31.6, 25.5, 24.7, 24.6.
2-(Decyloxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2ad).6e
Reaction time: 12 h. NMR yield: >99%. 1H NMR (400 MHz,
CDCl3): δ 3.76 (t, J = 6.5 Hz, 2H), 1.56−1.40 (m, 2H), 1.20 (s,
38H), 1.19 (s, 12H), 0.81 (t, J = 6.2 Hz, 3H). 13C NMR (101 MHz,
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J. Org. Chem. 2019, 84, 1570−1579