The Journal of Organic Chemistry
ARTICLE
4H), 7.15ꢀ7.10 (m, 1H), 3.03 (dd, J = 18.3, 10.8 Hz, 1H), 2.82 (dd, J =
18.3, 5.3 Hz, 1H), 2.63 (dd, J = 10.8, 5.3 Hz, 1H), 2.12 (s, 3H), 1.21 (s,
6H), 1.15 (s, 6H); 13C NMR (125 MHz, CDCl3) δ = 208.4, 141.8,
128.6, 128.3, 125.6, 83.5, 47.6, 29.7, 27.0, 24.6, 24.6; 11B NMR (160
MHz, CDCl3): δ = 32.16; IR (NaCl) 2978, 1713, 1366, 1319, 1144, 966,
854, 702 cmꢀ1; HRMS (ESIþ): Calcd for C16H24BO3 [M þ H]:
275.1819, Found: 275.1819; Calcd for C16H27BNO3 [M þ NH4]þ:
292.2084, Found: 292.2091.
1,3-Diphenyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-
2-yl)propan-1-one 9g: oil; 1H NMR (500 MHz, CDCl3) δ =
7.97ꢀ7.95 (m, 2H), 7.59ꢀ7.50 (m, 1H), 7.45ꢀ7.42 (m, 2H), 7.34ꢀ
7.24 (m, 4H), 7.21ꢀ7.13 (m, 1H), 3.55 (dd, J = 10.9, 18.3 Hz, 1H), 3.42
(dd, J = 5.0, 18.3 Hz, 1H), 2.80 (dd, J = 5.0, 10.9 Hz, 1H), 1.24 (s, 6H),
1.16 (s, 6H); 13C NMR (125 MHz, CDCl3) δ = 199.8, 142.0, 136.9,
133.0, 128.6, 128.6, 128.5, 128.1, 125.7, 83.5, 43.4, 27.3, 24.7, 24.6; 11B
NMR (160 MHz, CDCl3): δ = 32.63; IR (NaCl) 2978, 1682, 1367,
1321, 1142, 754, 698 cmꢀ1; HRMS (ESIþ): Calcd for C21H26BO3 [M þ
H]þ: 337.1975, Found: 337.1981.
CDCl3) δ = 9.76 (s, 1H), 2.58 (dd, J = 7.2, 18.0 Hz, 1H), 2.51 (dd, J =
7.2, 18.0 Hz, 1H), 1.53ꢀ1.46 (m, 1H), 1.43ꢀ1.36 (m, 1H), 1.32ꢀ1.26
(m, 1H), 1.24 (s, 6H), 1.23 (s, 6H), 0.92 (t, J = 7.4 Hz, 3H); 13C NMR
(125 MHz, CDCl3) δ = 203.0, 83.3, 45.6, 24.9, 24.7, 23.6, 13.3; 11B
NMR (160 MHz, CDCl3): δ = 33.74; IR (NaCl) 2977, 1725, 1368,
1318, 1146, 968, 854 cmꢀ1; HRMS (ESIþ): Calcd for C11H21BNaO3
[M þ Na]þ: 235.1481, Found: 235.1484.
2-Methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-
1
propanal 13: oil; TLC (5% EtOAc/hexanes): Rf = 0.21. H NMR
(400 MHz, CDCl3) δ = 9.64 (s, 1H), 2.56 (m, 1H), 1.25 (s, 6H), 1.24 (s,
6H), 1.15 (d, J = 7.2 Hz, 3H), 1.05 (dd, J = 6.9, 15.9 Hz, 1H), 0.83 (dd,
J = 7.7, 15.9 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ = 205.3, 83.4,
42.7, 24.8, 15.7; 11B NMR (160 MHz, CDCl3): δ = 33.38; IR (NaCl)
2979, 1723, 1369, 1319, 1147, 968, 852 cmꢀ1; HRMS (ESIþ): Calcd for
C10H19BNaO3 [MþNa]þ: 221.1325, Found: 221.1311.
([PDIPA B2][K(thf)])2, ((10)thf)2. Under an atmosphere of nitro-
gen 2 (70 mg, 260 μmol) and KOtBu (41 mg, 365 μmol, 1.4 equiv) were
combined in 2 mL of dry THF. After 3 d, X-ray quality crystals separated,
which were washed with n-hexane (2 ꢁ 2 mL) and dried in vacuo to give
27 mg (36 μmol, 27%) of a colorless solid. mp: > 160 °C dec; 1H NMR
(700 MHz, THF-d8): δ = 4.43ꢀ4.38 (m, 1 H, OCH(A)), 4.37ꢀ4.31 (m,
1 H, OCH(A0)), 4.15ꢀ4.09 (m, 1 H, OCH(B)), 3.63ꢀ3.60 (m, 4 H,
CH2O(THF)), 3.14 (t, J = 8 Hz, 1 H, CH2N(A)), 3.09 (t, J = 8 Hz, 1 H,
CH2N(A0)), 2.76ꢀ2.66 (m, 2 H, CH2N(A, B)), 2.59ꢀ2.55 (m, 2 H,
CH2N(A0, B)), 1.79ꢀ1.76 (m, 4 H, CH2O(THF)), 1.30 (d, JHH = 6 Hz,
3 H, CH3(A0)), 1.19 (d, J = 6 Hz, 3 H, CH3(A0)), 1.09, 1.07, 1.06 (two
signals) (s, 6 H, CH3(pin)), 1.04 (d, J = 6 Hz, 3 H, CH3(B)), 0.99 (two
signals) (s, 3 H, CH3(pin)), 0.95 (s, 3 H, CH3(pin)); 13C NMR (175
MHz, THF-d8): δ = 78.5, 78.4, 77.2, 77.0, 74.7, 74.1, 68.4, 66.1, 65.9,
58.2, 57ꢀ7, 57.4, 57.3, 27.6, 27.5, 27.3, 27.1 (two signals), 26.7 (two
signals), 26.6, 24.6, 23.1, 22.6; 11B NMR (224 MHz, THF-d8): δ = 38.1
(v br s), 5.4 (br s); Anal. Calcd for: C32H64O10N2B4K2: C, 50.68; H,
8.51; N, 3.67%. Found: C, 50.84; H, 8.58; N, 3.61%.
3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)cyclohexa-
none 9h: oil; TLC (20% EtOAC/hexanes): Rf = 0.37. 1H NMR (500
MHz, CDCl3) δ = 2.39ꢀ2.25 (m, 4H), 2.11ꢀ2.01 (m, 1H), 1.89ꢀ1.82
(m, 1H), 1.79ꢀ1.68 (m, 1H), 1.67ꢀ1.59 (m, 1H), 1.49ꢀ1.40 (m, 1H),
1.22 (s, 12H); 13C NMR (125 MHz, CDCl3) δ = 212.4, 83.5, 42.6, 41.9,
28.5, 26. 6, 25.1, 24.8, 24.8; 11B NMR (160 MHz, CDCl3): δ = 33.11; IR
(NaCl) 2978, 1711, 1383, 1327, 1144, 980, 851 cmꢀ1; HRMS (ESIþ):
Calcd for C12H22BO3 [M þ H]þ: 225.1662, Found: 225.1639.
3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)cyclopenta-
none 9i: oil; 1H NMR (500 MHz, CDCl3) δ = 2.34ꢀ2.17 (m, 2H),
2.16ꢀ2.04 (m, 3H), 1.88ꢀ1.77 (m, 1H), 1.69ꢀ1.55 (m, 1H), 1.23 (s,
12H); 13C NMR (125 MHz, CDCl3) δ = 221.1, 83.6, 40.5, 39.0, 25.3,
24.8, 24.8, 19.7; 11B NMR (160 MHz, CDCl3): δ = 33.48; IR (NaCl)
2978, 1742, 1385, 1323, 1144, 968, 858 cmꢀ1; HRMS (ESIþ): Calcd for
C11H20BO3 [M þ H]: 211.1506, Found: 211.1492; Calcd for C11H23-
BNO3 [M þ NH4]þ: 228.1771, Found: 228.1762.
X-ray Crystallographic Analysis. Crystals were centered on the
goniometer of an Oxford Diffraction SuperNova equipped with an Eos
detector and operating with Cu KR radiation (R,R)-2 or a Bruker
SMART 1000 ((10)thf)2 diffractometer using Mo KR radiation, re-
spectively. The data collection routine, unit cell refinement, and data
processing were carried out with the program CrysAlisPro ((R,R)-2)127
4-Methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-
pentan-2-one 9j: oil; 1H NMR (500 MHz, CDCl3) δ = 2.48 (s, 2H),
2.07 (s, 3H), 1.23 (s, 12H), 0.91 (s, 6H); 13C NMR (125 MHz, CDCl3)
δ = 208.8, 83.0, 55.8, 30.1, 24.7; 11B NMR (160 MHz, CDCl3): δ = 34.10;
IR (NaCl) 2976, 2934, 1715, 1367, 1308, 1140, 968, 858 cmꢀ1; HRMS
(ESIþ): Calcd for C12H24BO3 [M þ H]þ: 227.1819, Found: 227.1814.
3-Methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-
or SMART,128 SAINT129 and SADABS130 (((10)K thf)2). The struc-
3
tures were solved by direct methods and refined using SHELXTL NT or
SHELXTL 6.14.131 The final refinement model involved anisotropic
displacement parameters for all non-hydrogen atoms and a riding model
for all hydrogen atoms. In the case of (R,R)-2, the anisotropic displace-
ment parameters of the pinacol group suggest disorder, but attempts to
model 2-position disorder did not improve the overall model and were
abandoned. In the structure of ((10)thf)2, the THF molecule is partly
disordered; two positions were refined (ratio of occupancies: 54:46).
Additionally, a part of the diisopropanolamine moiety is disordered (see
text). The absolute configuration of (R,R)-2 was established from
anomalous dispersion effects (Flack x = ꢀ0.07(18);132 Hooft P2(true)
= 1.000, P3(true) = 1.000, P3(rac-twin) = 0.4 ꢁ 1015; P3(false) = 0.000,
y = ꢀ0.05(7)133). CCDC-750196 ((4R,8R)-2), CCDC-784473 (2) and
CCDC-784472 (((10)thf)2)) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of charge
ac.uk/data_request/cif.
1
pentan-2-one 9k: oil; H NMR (500 MHz, CDCl3) δ = 2.59 (m,
1.21H), 2.14 (s, 0.63H, minor diastereomer), 2.11 (s, 3H, major
diastereomer), 1.26 (m, 1.21H), 1.23 (s, 12H, major diastereomer),
1.21 (s, 2.52H, minor diastereomer), 1.13 (d, J = 7.2 Hz, 3H, major
diastereomer), 1.12 (d, J = 7.2 Hz, 0.63H, minor diastereomer), 0.91 (d,
J = 7.5 Hz, 3H, major diastereomer), 0.89 (d, J = 8.5 Hz, 0.63H, minor
diastereomer); 13C NMR (125 MHz, CDCl3): δ = 213.1, 83.1, 83.0,
50.1, 49.8, 28.2, 28.1, 24.8, 24.8, 15.7, 14.8, 13.0, 12.3; 11B NMR (160
MHz, CDCl3): δ = 33.63; IR (NaCl) 2976, 1711, 1369, 1317, 1146, 968,
856 cmꢀ1; HRMS (ESIþ): Calcd for C12H24BO3 [M þ H]þ: 227.1819.
1-(2-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)cyclo-
hexyl)ethanone 9l: oil; 1H NMR (500 MHz, CDCl3): δ = 2.57 (dt,
J = 4.5, 7.5 Hz, 1H, major diastereomer), 2.49 (dt, J = 6.5, 13.5 Hz, 0.1H,
minor diastereomer), 2.12 (s, 3.3H), 1.88ꢀ1.78 (m, 2.2H), 1.69ꢀ1.65
(m, 1.1H), 1.55ꢀ1.50 (m, 1.1H), 1.48ꢀ1.42 (m, 2.2H), 1.41ꢀ1.34 (m
2.2H), 1.29ꢀ1.26 (m, 1.1H), 1.22 (d, J = 4.3 Hz, 13.2H); 13C NMR
(125 MHz, CDCl3): δ = 212.1, 83.2, 82.8, 53.0, 52.2, 29.9, 27.9, 27.6,
27.6, 26.7, 26.7, 26.5, 25.8, 25.4, 25.2, 25.1, 24.9, 24.8, 24.8, 24.6, 24.6;
11B NMR (160 MHz, CDCl3): δ = 33.22; IR (NaCl) 2928, 2855, 1707,
1377, 1311, 1146, 970, 852 cmꢀ1; HRMS (ESIþ): Calcd for C14H26BO3
[M þ H]þ: 253.1975, Found: 253.1993.
X-ray data for (R,R)-2: C12H25B2NO4, Mr = 268.95, crystal
dimensions 0.211 ꢁ 0.072 ꢁ 0.066 mm3, orthorhombic, P212121, a =
9.5436(2) Å, b = 11.7206(3) Å, c = 13.6397(3) Å, V = 1525.69(6) Å3,
Z = 4, Z0 = 1, Fcalcd = 1.171 g/cm3, μ = 0.673 mmꢀ1, Cu KR radiation
(1.5418 Å), T = 100(2) K, 2θmax = 144.5°, 9951 reflections with 2992
unique [R(int) = 0.0274], R1= 0.0365 (for 2852 unique data with I >
2σ(I)), wR2 = 0.994 (all data), max peak/hole = 0.246/ꢀ0.205 eꢀ/Å3.
3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)pentanal
1
12: oil; TLC (5% EtOAc/hexanes): Rf = 0.30. H NMR (500 MHz,
4004
dx.doi.org/10.1021/jo2003488 |J. Org. Chem. 2011, 76, 3997–4007