6414
M. Van Overschelde et al. / Tetrahedron 65 (2009) 6410–6415
812, 750, 665, 641. ESI-MS m/z (rel intensity) 256 (90), 232 (100),
215 (82, [MꢂH]þ); EIMS m/z (rel intensity) 215 (2, [MꢂH]þ), 202
(29, [MꢂBH3]þ), 172 (2), 157 (4), 146 (28, [MꢂBH3ꢂC4H8]þ), 116 (3),
101 (4), 91 (16), 90 (16), 57 (100, [C4H9]þ), 41 (50). Anal. Calcd for
C12H30BP: C, 66.68; H, 13.99. Found: C, 66.49; H, 14.05.
129.0 (d, J¼55.2 Hz, C), 128.9 (d, J¼9.9 Hz, CH), 26.7 (dd, J¼36.3,
11.1 Hz, CH2), 17.4 (s, CH2); 31P NMR (121 MHz, CDCl3)
15.8 (br).
d
IR (KBr, cmꢂ1) 3077, 3057, 2941, 2931, 2904, 2382 (BH3), 2261
(BH3), 2119, 1972, 1897, 1814, 1669, 1559, 1485, 1456, 1414, 1331,
1312, 1265, 1185, 1161, 1132, 1110, 1061, 1028, 999, 964, 827, 737,
702, 694. ESI-MS m/z (rel intensity) 463 (37, [MþNa]þ), 458 (100,
[MþNH4]þ), 441 (28, [MþH]þ), 439 (45, [MꢂH]þ), 427 (23,
[MꢂBH3þH]þ), 413 (18, [Mꢂ2BH3þH]þ); EIMS m/z (rel intensity)
439 (1, [MꢂH]þ), 425 (61, [MꢂBH4]þ), 412 (6, [Mꢂ2BH3]þ), 335
(32), 315 (3), 294 (5), 289 (4), 259 (6), 237 (10), 227 (8), 199 (18),
186 (17), 185 (28, [PPh2]þ), 183 (100), 165 (27), 152 (17), 133 (12),
121 (33), 109 (49), 108 (51, [PPh]þ), 91 (21, [C7H7]þ), 89 (33), 78
(24), 77 (20), 51 (18), 41 (5). Anal. Calcd for C27H32B2P2: C, 73.68;
H, 7.33. Found: C, 73.92; H, 7.36.
4.2.7. Tricyclohexylphosphane-borane(1:1) (7a)
White solid; yield 62%; mp 179 ꢀC. 1H NMR (300 MHz, CDCl3)
d
2.05–1.55 (m, 18H, Cy-H), 1.50–1.10 (m, 15H, Cy-H), 0.90–(ꢂ0.35)
(br, 3H, BH3); 13C NMR (75 MHz, CDCl3)
30.9 (d, J¼30.5 Hz, CH),
27.8 (d, J¼1.7 Hz, CH2), 27.3 (d, J¼10.3 Hz, CH2), 26.1 (d, J¼0.8 Hz,
CH2); 31P NMR (121 MHz, CDCl3) 28.0 (br). IR (KBr, cmꢂ1) 2924,
d
d
2851, 2361 (BH3), 2338 (BH3), 1445, 1406. ESI-MS m/z (rel intensity)
611 (8, [2MþNa]þ), 332 (13), 317 (8, [MþNa]þ), 310 (42), 297 (4,
[Cy3P(O)þH]þ), 291 (100, [Mꢂ3H]þ); EIMS m/z (rel intensity) 280
(29, [MꢂBH3]þ), 209 (4), 199 (22), 198 (53), 143 (4), 117 (41), 116
(12), 115 (18), 83 (39, [Cy]þ), 81 (26), 69 (17), 55 (100), 53 (14), 41
(51). Anal. Calcd for C18H36BP: C, 73.47; H, 12.33. Found: C, 73.31; H,
12.29.
4.2.12. 1,10-Bis(diphenylphosphanyl)ferrocene-borane(1:2) (12a)24
Orange solid; yield 100%; mp 191 ꢀC. 1H NMR (300 MHz, CDCl3)
d
7.55–7.30 (m, 20H, Ph-H), 4.53 (m, 4H, Cp-H), 4.25 (m, 4H, Cp-H),
2.45–0.50 (br, 6H, BH3); 13C NMR (75 MHz, CDCl3)
d
132.5 (d,
J¼9.6 Hz, CH), 131.1 (d, J¼2.3 Hz, CH), 130.7 (d, J¼59.4 Hz, C), 128.5
(d, J¼10.2 Hz, CH), 74.6 (d, J¼7.5 Hz, CH), 73.9 (d, J¼9.7 Hz, CH), 70.4
4.2.8. Trimethyl phosphite-borane(1:1) (8a)20
Colorless, clear oil; yield 100%. 1H NMR (300 MHz, CDCl3)
d
3.73
(d, J¼66.9 Hz, C); 31P NMR (121 MHz, CDCl3)
d 15.7 (br). IR (KBr,
(d, J¼11.1 Hz, 9H, CH3), 0.43 (br q, J¼96.3 Hz, 3H, BH3); 13C NMR
cmꢂ1) 3070, 2889, 2377 (BH3), 2248 (BH3), 2047, 1685, 1594, 1571,
1437, 1310, 1173, 1104, 1057, 897, 835, 737, 703. ESI-MS m/z (rel in-
tensity) 605 (26, [MþNa]þ), 600 (100, [MþNH4]þ), 581 (36,
[MꢂH]þ), 569 (5, [MꢂBH3þH]þ); EIMS m/z (rel intensity) 554 (26,
[Mꢂ2BH3]þ), 477 (9, [Mꢂ2BH3ꢂPh]þ), 370 (20), 293 (4), 263 (4),
250 (4), 226 (11), 186 (21), 185 (20, [PPh2]þ), 171 (38), 170 (38), 149
(16), 120 (20), 115 (21), 108 (32, [PPh]þ), 107 (26), 84 (100), 77 (32,
[Ph]þ), 40 (25). Anal. Calcd for C34H34B2FeP2: C, 70.16; H, 5.89.
Found: C, 70.02; H, 5.91.
(75 MHz, CDCl3)
d
d
53.2 (d, J¼3.8 Hz, CH3); 31P NMR (121 MHz, CDCl3)
119.3 (q, J¼100.0 Hz). IR (KBr, cmꢂ1) 2360 (BH3). APCI-MS m/z (rel
intensity) 125 (100, [MꢂBH3þH]þ), 93 (5, [MꢂBH3ꢂCH3OHþH]þ);
EIMS m/z (rel intensity) 124 (87, [MꢂBH3]þ), 121 (11), 93 (100,
[MꢂBH3ꢂOCH3]þ), 82 (28), 79 (18), 59 (18), 58 (12).
4.2.9. Triethyl phosphite-borane(1:1) (9a)21
Colorless, clear oil; yield 100%. 1H NMR (300 MHz, CDCl3)
d
4.07
(m, 6H, CH2), 1.32 (t, J¼7.0 Hz, 9H, CH3), 0.40 (br q, J¼93.0 Hz, 3H,
BH3); 13C NMR (75 MHz, CDCl3)
d
62.6 (d, J¼3.3 Hz, CH2), 16. 2 (d,
4.2.13. Diphenylphosphane-borane(1:1) (13a)25
J¼5.6 Hz, CH3); 31P NMR (121 MHz, CDCl3)
d
114.0 (q, J¼101.6 Hz). IR
White crystalline solid; yield 97%; mp 40 ꢀC. 1H NMR (300 MHz,
(KBr, cmꢂ1) 2982, 2943, 2909, 2396 (BH3), 1456, 1392, 1162, 1130,
1102, 1016, 974, 953, 914, 884, 796. APCI-MS m/z (rel intensity) 167
(100, [MꢂBH3þH]þ), 139 (97), 121 (25, [MꢂBH3ꢂEtOHþH]þ), 111
(40), 93 (11), 83 (89); EIMS m/z (rel intensity) 166 (20, [MꢂBH3]þ),
149 (26), 139 (20), 128 (19), 107 (23), 93 (71), 86 (100), 69 (43), 57
(88), 48 (48).
CDCl3)
d
7.82–7.34 (m, 10H, Ph-H), 6.30 (dq, J¼379, 6.9 Hz, 1H, P-H),
1.07 (br q, J¼90.9 Hz, 3H, BH3); 13C NMR (75 MHz, CDCl3)
d 133.0 (d,
J¼9.4 Hz, CH), 131.7 (d, J¼2.5 Hz, CH), 129.1 (d, J¼10.3 Hz, CH), 126.3
(d, J¼57.2 Hz, C); 31P NMR (121 MHz, CDCl3)
d )
1.4 (br). IR (KBr, cmꢂ1
3200, 3053, 2394 (BH3),1970,1886,1666,1584,1441,1117,1057, 900,
810, 753, 699. ESI-MS m/z (rel intensity) 427 (6, [2HP(O)Ph2þNa]þ),
405 (13, [2HP(O)Ph2þH]þ), 225 (7, [HP(O)Ph2þNa]þ), 203 (100,
[HP(O)Ph2þH]þ); EIMS m/z (rel intensity) 197 (19, [Mꢂ3H]þ), 186
(100, [MꢂBH3]þ),170 (3),165 (11),152 (10),139 (6),119 (13),109 (64,
[HPPh]þ), 108 (96, [PPh]þ), 107 (67), 89 (51), 78 (26), 77 (30, [Ph]þ),
63 (28), 51 (54). Anal. Calcd for C12H14BP: C, 72.06; H, 7.05. Found: C,
72.02; H, 7.08.
4.2.10. Methylenebis(diphenylphosphane)-borane(1:2) (10a)22
White crystalline solid; yield 94%; mp 213 ꢀC. 1H NMR
(300 MHz, CDCl3)
H4), 7.34 (m, 8H, Ph-H2 and H6), 3.24 (t, J¼10.9 Hz, 2H, CH2), 1.40–
0.40 (br, 6H, BH3); 13C NMR (75 MHz, CDCl3)
d 7.64 (m, 8H, Ph-H3 and H5), 7.43 (m, 4H, Ph-
d
132.7 (d, J¼9.9 Hz,
CH), 131.6 (d, J¼2.3 Hz, CH), 128.8 (d, J¼10.3 Hz, CH), 128.4 (dd,
J¼56.4, 2.4 Hz, C), 23.8 (t, J¼24.8 Hz, CH2); 31P NMR (121 MHz,
4.3. Synthesis of the substrates 14a–16a
CDCl3)
d
14.6 (br). IR (KBr, cmꢂ1) 2409 (BH3), 2359 (BH3), 2343
(BH3), 1485, 1437, 1366, 1312, 1167, 1104, 1056, 1027, 999, 808, 798,
767, 751, 742, 712, 694. APCI-MS m/z (rel intensity) 471 (8), 455
To a solution of the chlorodiarylphosphane (66 mmol) in THF
(30 mL), a solution of borane–THF in THF (1 M; 100 mL) was added
at 0 ꢀC. After stirring for 2 h, LiAlH4 (82 mmol) was added in small
portions. The reaction was stirred for another 2 h at 0 ꢀC, upon
which it was carefully quenched into a mixture of concentrated HCl
(37% aq; 50 mL) and ice. The product was extracted with toluene
(3ꢁ100 mL) and the combined organic phase dried (Na2SO4) and
concentrated. Purification by flash chromatography yielded the
isolated secondary phosphane-boranes 14a–16a.
(7),
417
(35,
[Ph2P(O)CH2P(O)Ph2þH]þ),
401
(100,
[Ph2P(O)CH2PPh2þH]þ), 385 (53, [Mꢂ2BH3þH]þ); EIMS m/z (rel
intensity) 409 (1, [Mꢂ3H]þ), 398 (1, [MꢂBH3]þ), 384 (4,
[Mꢂ2BH3]þ), 320 (3), 308 (12), 262 (22), 232 (1), 199 (18), 186
(10), 185 (10, [PPh2]þ), 183 (31), 165 (14), 152 (7), 133 (3), 121 (47),
109 (6), 108 (23, [PPh]þ), 107 (18), 85 (43), 84 (62), 78 (11), 77 (16,
[Ph]þ), 51 (46), 49 (100), 48 (15), 47 (23). Anal. Calcd for
C25H28B2P2: C, 72.87; H, 6.85. Found: C, 72.61; H, 6.88.
4.3.1. Di(3,5-dimethylphenyl)phosphane-borane(1:1) (14a)
Purified by flash chromatography on silica gel (eluent: n-pen-
tane/toluene 8:2); white crystalline solid; yield 65%; mp 106 ꢀC. 1H
4.2.11. Propane-1,3-diyl-bis(diphenylphosphane)-borane(1:2)
(11a)23
White foam; yield 92%; mp 155 ꢀC. 1H NMR (300 MHz, CDCl3)
NMR (300 MHz, CDCl3)
(s, 2H, Ar-H4), 6.19 (dq, J¼377, 6.9 Hz, 1H, P-H), 2.36 (s, 12H, ArCH3),
1.77–0.41 (br, 3H, BH3); 13C NMR (75 MHz, CDCl3)
138.8 (d,
J¼10.6 Hz, C), 133.4 (d, J¼2.3 Hz, CH), 130.5 (d, J¼9.8 Hz, CH), 126.2
d
7.28 (d, J¼12.1 Hz, 4H, Ar-H2 and H6), 7.15
d
7.60 (m, 8H, Ph-H3), 7.51–7.36 (m, 12H, Ph-H2 and H4), 2.33 (m,
4H, H1 and H3), 1.72 (m, 2H, H2), 1.52–0.25 (br, 6H, BH3); 13C NMR
(75 MHz, CDCl3)
132.1 (d, J¼9.1 Hz, CH), 131.3 (d, J¼2.3 Hz, CH),
d
d