K. Ikegai et al.
Bull. Chem. Soc. Jpn. Vol. 79, No. 5 (2006)
787
2H), 1.58 (d, J ¼ 5:8 Hz, 3H), 0.91 (q, J ¼ 7:3 Hz, 3H); 13C NMR
(68 MHz, CDCl3) ꢁ 173.7, 143.3, 143.0, 142.6, 142.4, 135.4,
130.3, 130.1, 130.0, 129.8, 128.9, 128.6, 128.3, 128.1, 128.0 (ꢄ3),
127.9, 127.8, 82.2 (d, J ¼ 13 Hz), 66.8, 33.6 (d, J ¼ 6 Hz), 24.2
(d, J ¼ 12 Hz), 8.4; HRMS (APCIþ) Calcd for C24H26O3P: ½M þ
Hꢃþ 393.1620. Found: m=z 393.1605.
diphenylphosphinate was confirmed by TLC monitoring and the
crude product was directly purified by preparative TLC on silica-
gel (haxane/EtOAc, 90/10 or 95/5) to afford the desired Btz
sulfide 2.
3,5-Di-t-butyl-4-hydroxyphenyl
(Scheme 1): White solid; mp 170–171 ꢂC; IR (ATR, cmꢁ1
3221, 2950, 1590, 1428, 1218, 1176, 1130, 1109, 985, 970, 860,
Diphenylphosphinate
)
(S)-Ethyl 2-[(Diphenylphosphino)oxy]-2-methyl-3-phenyl-
24
1
propionate (1k): Colorless oil; ½ꢀꢃD ꢁ11:8 (c 1.14, CHCl3);
730, 693, 547, 527; H NMR (270 MHz, CDCl3) ꢁ 7.94–7.87 (m,
IR (neat, cmꢁ1) 1738, 1103, 742, 698; 1H NMR (270 MHz,
CDCl3) ꢁ 7.50–7.18 (m, 15H), 4.07 (q, J ¼ 7:1 Hz, 2H), 3.24 (d,
J ¼ 13:5 Hz, 1H), 3.15 (d, J ¼ 13:5 Hz, 1H), 1.57 (s, 3H), 1.03 (t,
J ¼ 7:1 Hz, 3H); 13C NMR (68 MHz, CDCl3) ꢁ 173.4, 143.4,
143.1, 142.4, 142.2, 135.7, 130.7, 130.5, 130.1, 130.0, 129.7,
128.9, 128.4, 128.1, 128.0, 127.7 (ꢄ2), 126.7, 82.1 (d,
J ¼ 13 Hz), 61.2, 46.9 (d, J ¼ 4 Hz), 24.2 (d, J ¼ 13 Hz), 13.9;
HRMS (APCIþ) Calcd for C24H26O3P: ½M þ Hꢃþ 393.1620.
Found: m=z 393.1607.
4H), 7.53–7.46 (m, 6H), 6.85 (s, 2H), 5.00 (s, 1H), 1.30 (s, 18H);
13C NMR (68 MHz, CDCl3) ꢁ 150.3, 143.0 (d, J ¼ 8 Hz), 136.8,
132.3, 132.1, 132.1, 131.8, 131.6, 130.2, 128.4, 128.2, 117.3,
117.2, 34.3, 30.0; HRMS (APCIþ) Calcd for C26H32O3P: ½M þ
Hꢃþ 423.2089. Found: m=z 423.2083.
Methyl 2-Methyl-2-[(4-nitrophenyl)sulfanyl]propionate
(2a): Colorless oil; IR (ATR, cmꢁ1) 1727, 1516, 1341, 1266,
1152, 1121, 851; 1H NMR (270 MHz, CDCl3) ꢁ 8.16 (ddd, J ¼
2:1, 2.5, 8.9 Hz, 2H), 7.57 (ddd, J ¼ 2:1, 2.5, 8.9 Hz, 2H), 3.71 (s,
3H), 1.56 (s, 6H); 13C NMR (68 MHz, CDCl3) ꢁ 173.6, 147.5,
140.8, 135.1, 123.3, 52.5, 51.5, 25.9; HRMS (FABþ) Calcd for
C11H14NO4S: ½M þ Hꢃþ 256.0644. Found: m=z 256.0652.
Methyl 2-Methyl-2-[(5-nitropyridin-2-yl)sulfanyl]propio-
nate (2b): Colorless oil; IR (ATR, cmꢁ1) 1731, 1585, 1566,
1511, 1339, 1264, 1099, 854, 750; 1H NMR (270 MHz, CDCl3)
ꢁ 9.17 (d, J ¼ 2:7 Hz, 1H), 8.23 (dd, J ¼ 2:7, 8.7 Hz, 1H), 7.26
(d, J ¼ 8:7 Hz, 1H), 3.71 (s, 3H), 1.72 (s, 6H); 13C NMR
(68 MHz, CDCl3) ꢁ 174.0, 166.0, 144.3, 140.9, 130.3, 121.2,
52.8, 51.6, 26.1; HRMS (FABþ) Calcd for C10H13N2O4S: ½M þ
Hꢃþ 257.0596. Found: m=z 257.0582.
(S)-Methyl 2-[(Diphenylphosphino)oxy]-2-phenylpropionate
22
(1l): Colorless oil; ½ꢀꢃD ꢁ5:9 (c 1.33, CHCl3); IR (ATR, cmꢁ1
)
1742, 1227, 1125, 1103, 692; 1H NMR (270 MHz, CDCl3) ꢁ 7.61–
7.48 (m, 6H), 7.39–7.24 (m, 9H), 3.63 (s, 3H), 1.91 (s, 3H);
13C NMR (68 MHz, CDCl3) ꢁ 173.2, 142.6, 142.4, 142.2, 142.0,
141.7, 141.7, 130.6, 130.4, 130.3, 130.1, 129.1, 128.8, 128.2
(ꢄ2), 128.1 (ꢄ2), 128.0, 127.9, 125.4, 82.8 (d, J ¼ 16 Hz),
52.4, 26.5 (d, J ¼ 12 Hz); HRMS (EI) Calcd for C22H21O3P:
[M]þ 364.1228. Found: m=z 364.1215.
(S)-1-Ethyl-1-methyl-3-phenylpropyl Diphenylphosphinite
19
(1m): Colorless oil; ½ꢀꢃD þ3:5 (c 1.01, CHCl3); IR (ATR,
cmꢁ1) 908, 739, 693; 1H NMR (270 MHz, CDCl3) ꢁ 7.60–7.46
(m, 4H), 7.40–7.00 (m, 11H), 2.63–2.54 (m, 2H), 2.04–1.90 (m,
2H), 1.80 (q, J ¼ 7:4 Hz, 2H), 1.38 (s, 3H), 0.90 (t, J ¼ 7:4 Hz,
3H); 13C NMR (68 MHz, CDCl3) ꢁ 143.9, 143.8, 143.6 (ꢄ2),
142.5, 130.2, 130.1, 129.8 (ꢄ2), 128.6 (ꢄ2), 128.2, 128.1, 128.0,
125.5, 81.0 (d, J ¼ 10 Hz), 42.2 (d, J ¼ 7 Hz), 33.2 (d, J ¼ 7
Hz), 30.4, 25.3 (d, J ¼ 11 Hz), 8.7; HRMS (APCIþ) Calcd for
C24H28OP: ½M þ Hꢃþ 363.1878. Found: m=z 363.1877.
Methyl 2-[(1,3-Benzothiazol-2-yl)sulfanyl]-2-methylpropio-
nate (2c): Colorless oil; IR (neat, cmꢁ1) 1737, 1459, 1429,
1267, 1157, 1126, 989; 1H NMR (270 MHz, CDCl3) ꢁ 7.92 (d,
J ¼ 8:2 Hz, 1H), 7.76 (d, J ¼ 7:7 Hz, 1H), 7.50–7.22 (m, 2H),
3.74 (s, 3H), 1.74 (s, 6H); 13C NMR (68 MHz, CDCl3) ꢁ 173.5,
161.0, 153.0, 136.1, 125.9, 124.8, 122.3, 120.8, 53.8þ, 52.8, 26.3;
HRMS (FABþ) Calcd for C12H14NO2S2: ½M þ Hꢃ 268.0466.
Found: m=z 268.0479.
(S)-1-Methyl-1-phenylpropyl Diphenylphosphinite (1n):
Methyl 2-[(1,3-Benzoxazol-2-yl)sulfanyl]-2-methylpropio-
nate (2d): IR (ATR, cmꢁ1) 1736, 1503, 1452, 1118, 1091, 743;
1H NMR (270 MHz, CDCl3) ꢁ 7.64–7.54 (m, 1H), 7.46–7.36 (m,
1H), 7.30–7.17 (m, 2H), 3.71 (s, 3H), 1.76 (s, 6H); 13C NMR
(68 MHz, CDCl3) ꢁ 173.1, 161.2, 151.3, 141.5, 124.3, 124.1,
119.0, 109.8, 53.0, 52.9, 26.5; HRMS (FABþ) Calcd for C12H14-
NO3S: ½M þ Hꢃþ 252.0694. Found: m=z 252.0693.
22
White solid; mp 83–85 ꢂC; ½ꢀꢃD ꢁ6:40 (c 1.09, CHCl3); IR
1
(KBr, cmꢁ1) 916, 694; H NMR (270 MHz, CDCl3) ꢁ 7.63–7.16
(m, 15H), 2.22–1.89 (m, 2H), 1.70 (s, 3H), 0.70 (t, J ¼ 7:4 Hz,
3H); 13C NMR (68 MHz, CDCl3) ꢁ 145.8 (ꢄ2), 143.7, 143.4,
143.2, 130.4, 130.3, 130.0 (ꢄ2), 128.7, 128.6, 128.1 (ꢄ2), 128.0
(ꢄ2), 127.9, 126.7, 125.8 (ꢄ2), 82.6 (d, J ¼ 13 Hz), 36.6 (d,
J ¼ 6 Hz), 27.2 (d, J ¼ 13 Hz), 8.8; HRMS (FABþ) Calcd for
C22H24OP: ½M þ Hꢃþ 335.1565. Found: m=z 335.1555.
Benzyl 2-[(1,3-Benzothiazol-2-yl)sulfanyl]-2-methylpropio-
nate (2e): Colorless oil; IR (neat, cmꢁ1) 1734, 1459, 1428,
1
(R)-1-Isopropyl-4-methyl-3-cyclohexenyl Diphenylphos-
1260, 1155, 989; H NMR (270 MHz, CDCl3) ꢁ 7.84 (d, J ¼ 8:1
16
phinite (1o): Colorless crystal; 63–65 ꢂC; ½ꢀꢃD ꢁ8:1 (c 0.75,
Hz, 1H), 7.73 (d, J ¼ 7:9 Hz, 1H), 7.44–7.18 (m, 7H), 5.17 (s,
2H), 1.78 (s, 6H); 13C NMR (68 MHz, CDCl3) ꢁ 172.9, 161.8,
153.1, 136.1, 135.4, 128.2, 127.9, 127.8, 125.9, 124.8, 122.4,
120.8, 67.4, 54.0, 26.4; HRMS (FABþ) Calcd for C18H18NO2S2:
½M þ Hꢃþ 344.0779. Found: m=z 344.0792.
CHCl3); IR (ATR, cmꢁ1) 1433, 922, 902, 744, 697; 1H NMR
(270 MHz, CDCl3) ꢁ 7.54–7.40 (m, 4H), 7.34–7.18 (m, 6H), 5.26
(brs, 1H), 2.50–2.35 (m, 1H), 2.25–1.45 (m, 9H), 0.89 (d, J ¼ 6:9
Hz, 3H), 0.82 (d, J ¼ 6:9 Hz, 3H); 13C NMR (68 MHz, CDCl3) ꢁ
144.1, 143.9, 133.8, 131.1, 130.7, 129.5, 129.2, 128.8, 128.1,
127.9, 127.8 (ꢄ2), 127.7, 118.5, 81.1 (d, J ¼ 9 Hz), 35.8 (d, J ¼
5 Hz), 32.5 (d, J ¼ 11 Hz), 30.0 (d, J ¼ 8 Hz), 28.0, 23.1, 17.7,
17.2; HRMS (APCIþ) Calcd for C22H28OP: ½M þ Hꢃþ 339.1878.
Found: m=z 339.1863.
t-Butyl 2-[(1,3-Benzothiazol-2-yl)sulfanyl]-2-methylpropio-
nate (2f): White solid; mp 40–42 ꢂC; IR (KBr, cmꢁ1) 1728,
1
1458, 1425, 1272, 1151, 991; H NMR (270 MHz, CDCl3) ꢁ 7.90
(d, J ¼ 7:9 Hz, 1H), 7.76 (d, J ¼ 7:9 Hz, 1H), 7.48–7.22 (m, 2H),
1.73 (s, 6H), 1.42 (s, 9H); 13C NMR (68 MHz, CDCl3) ꢁ 171.9,
162.4, 153.1, 136.1, 125.8, 124.6, 122.1, 120.8, 81.6, 54.7, 27.7,
26.5; HRMS (FABþ) Calcd for C15H20NO2S2: ½M þ Hꢃþ
310.0935. Found: m=z 310.0954.
2-[(1,3-Benzothiazol-2-yl)sulfanyl]-2-methylpropiophenone
(2g): White solid; mp 41–42 ꢂC; IR (neat, cmꢁ1) 1678, 1455,
1252, 984; 1H NMR (270 MHz, CDCl3) ꢁ 8.10 (d, J ¼ 7:7 Hz,
General Procedure for Condensation of Alkyl Diphenyl-
phosphinites with Btz-SH. To a suspension of the diphenyl-
phosphinite 1 (1.0 mmol) and Btz-SH (83.6 mg, 0.5 mmol) in 0.5
mL of CHCl3 was added DBBQ (220 mg, 1.0 mmol) at rt. Btz-
SH gradually dissolved as the reaction proceeded. After 12–24 h,
the formation of 2 together with 3,5-di-t-butyl-4-hydroxyphenyl