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Organic & Biomolecular Chemistry
crystalline solid (15.02 g, 97%); mp 87–88 °C (lit.,34–36 colourless oil (1.60 g, 79%); νmax(film)/cm−1 1731 (CvO); δH
88–89 °C); νmax(KBr)/cm−1 1734 (CvO), 1447, 1261, 1126, (300 MHz, CDCl3) 1.29 (3H, d, J 6.9, CH3), 1.43 (3H, d, J 6.5,
1040; δH (300 MHz, CDCl3) 1.27–2.38 (8H, m, 4 × CH2ring), CH3), 3.21 (1H, A of ABq, J 14.7, one of SCH2), 3.28 (1H, qd,
3.00 (1H, ddd appears as dt, J 10.7, 10.7, 4.5, CHS), 3.23 (1H, J 6.9, 2.7, CHS), 3.58 (1H, B of ABq, J 14.7, one of SCH2), 4.66
A of ABq, J 15.0, one of SCH2), 3.69 (1H, B of ABq, J 15.0, (1H, qd, J 6.5, 2.6, CHO); δC (75.5 MHz, CDCl3) 16.1, 17.8
one of SCH2), 4.17 (1H, ddd appears as dt, J 10.7, 10.7, (2 × CH3), 26.0 (CH2, SCH2), 37.3 (CH, CHS), 77.1 (CH, CHO),
4.5, CHO); δC (75.5 MHz, CDCl3) 23.7 (CH2, SCH2), 25.1, 168.3 (CvO). Found (HRMS, EI): m/z 146.0395. C6H10O2S
26.8, 32.2, 32.6 (4 × CH2ring), 43.1 (CH, CHS), 81.6 (CH, CHO), requires M+ 146.0402; 146 (M+, 48%), 120 (5), 104 (12), 87 (8),
168.2 (CvO).
74 (45), 60 (100), 56 (52), 45 (31), 41 (40).
trans-8a-Methyl-hexahydrobenzo[b][1,4]oxathiin-2(3H)-one
trans-5,6-Dimethyl-[1,4]oxathian-2-one 24. From cis-2,3-
20. Note epoxide (10) was prepared by m-CPBA oxidation of dimethyl-oxirane 14 (1.04 mL, 12.00 mmol); purification by
1-methyl-cyclohexene.37,38 Pure product colourless oil (1.02 g, column chromatography (ethyl acetate–hexane 20 : 80) gave a
62%); νmax(film)/cm−1 1725 (CvO); δH (300 MHz, CDCl3) colourless oil (0.81 g, 40%); νmax(film)/cm−1 1742 (CvO); δH
1.25–1.90 (10H, m containing s at 1.58, 7 of H of CH2ring and (300 MHz, CDCl3) 1.32 (3H, d, J 6.7, CH3), 1.44 (3H, d, J 6.2,
CH3), 2.05 (1H, br d, J 11.9, 1 of H of CH2ring), 3.12 (1H, dd, CH3), 3.11 (1H, dq, J 13.3, 6.7, CHS), 3.21 (1H, A of ABq, J 14.8,
J 12.1, 3.7, CHS), 3.46 (1H, A of ABq, J 16.8, SCH2), 3.64 (1H, B one of SCH2), 3.67 (1H, B of ABq, J 14.8, one of SCH2), 4.30
of ABq, J 16.8, SCH2); δC (75.5 MHz, CDCl3) 19.3 (CH3), 22.5 (1H, dq, J 13.3, 6.2, CHO); δC (75.5 MHz, CDCl3) 18.6, 19.1
(CH2, SCH2), 25.6, 28.4, 28.6, 39.1 (4 × CH2ring), 46.0 (CH, (2 × CH3), 26.7 (CH2, SCH2), 39.8 (CH, CHS), 80.5 (CH, CHO),
CHS), 86.2 (C–Me), 166.3 (CvO). Found (HRMS, EI): m/z 168.3 (CvO). Found (HRMS, EI): m/z 146.0397. C6H10O2S
186.0725. C9H14O2S requires M+ 186.0715; 186 (M+, 50%), requires M+ 146.0402; 146 (M+, 70%), 118 (5), 111 (18),
156 (8), 144 (13), 111 (15), 96 (72), 86 (88), 81 (47), 71 (19), 104 (15), 87 (6), 74 (73), 60 (100), 45 (32), 41 (55).
55 (15), 43 (48), 32 (100).
cis-5,6-Diphenyl-[1,4]-oxathian-2-one 25.41 From trans-stil-
trans-Hexahydro-2H-cyclopenta[b][1,4]oxathiin-2-one 21.39. bene oxide 15 (3.00 g, 15.29 mmol); purification by column
From cyclopentene oxide 11 (1.04 mL, 12.00 mmol); recrystalli- chromatography (ethyl acetate–hexane 10 : 90) gave a white
zation from dichloromethane/hexane gave
a white solid crystalline solid (2.60 g, 63%); mp 145–147 °C (recrystallized
(0.490 g, 26%) which was found to be unstable and decom- from dichloromethane/hexane); νmax(KBr)/cm−1 1752 (CvO);
posed to complex mixture of unidentifiable products after δH (300 MHz, CDCl3) 3.53 (1H, A of ABq, J 14.4, 0.5, one of
24 h, mp 56–58 °C; νmax(KBr)/cm−1 1744 (CvO), 1466, 1269, SCH2), 3.99 (1H, B of ABq, J 14.4, SCH2), 4.55 (1H, d, J 3.3,
1143, 973; δH (300 MHz, CDCl3) 1.46–2.29 (6H, m, 3 × CH2ring), CHS), 5.74 (1H, d, J 3.2, CHO), 6.87–7.04 (4H, m, ArH),
3.09 (1H, ddd appears as dt, J 10.2, 10.2, 7.3, CHS), 3.29 (1H, A 7.08–7.25 (6H, m, ArH); δC (75.5 MHz, CDCl3) 28.0 (CH2,
of ABq, J 14.7, one of SCH2CO), 3.67 (1H, B of ABq, J 14.7, one SCH2), 49.4 (CH, CHS), 81.6 (CH, CHO), 126.0, 127.9, 128.1,
of SCH2CO), 4.47 (1H, ddd appears as dt, J 10.2, 10.0, 7.9, 128.3, 129.7 (CH, ArCH), 135.1, 136.0 (C), 168.2 (CvO). Found
CHO); δC (75.5 MHz, CDCl3) 20.0, 26.4, 28.3, 28.6 (3 × CH2ring (HRMS, EI): m/z 270.0705. C16H14O2S requires M+ 270.0715;
and SCH2CO), 42.4 (CH, CHS), 85.6 (CH, CHO), 168.6 (CvO). 270 (M+, 11%), 180 (53), 122 (100), 91 (17), 77 (40), 44 (39).
Found (HRMS, EI): m/z 159.0459. C7H11O2S requires M+
trans-5,6-Diphenyl-[1,4]-oxathian-2-one 26.41 From cis-stil-
159.0480; 159 (M+ + 1, 40%), 149 (23), 125 (7), 111 (53), 97 (31), bene oxide 16 (1.34 g, 6.83 mmol); purification by column
91 (15), 83 (38), 67 (100), 57 (24), 43 (52), 36 (3), 32 (22).
trans-Octahydro-2H-cyclohepta[b][1,4]oxathiin-2-one
chromatography (diethyl ether–hexane 50 : 50) gave a colour-
22. less oil (0.760 g, 41%); νmax(film)/cm−1 1754 (CvO);
From cycloheptene oxide 12 (8.349 g, 74.4 mmol); purification δH (270 MHz, CDCl3) 3.49 (1H, A of ABq, J 14.4, one of SCH2),
by column chromatography (hexane–ether 7 : 3) gave a white 4.06 (1H, B of ABq, J 14.4, SCH2), 4.44 (1H, d, J 11.0, CHS),
solid (2.770 g, 20%); mp 44–45 °C; (Found C, 58.16; H, 7.58; S, 5.45 (1H, d,
J 11.0, CHO), 6.93–7.35 (10H, m, ArH).
17.58. C9H14O2S requires C, 58.03; H, 7.27; S, 17.21%); δC (67.8 MHz, CDCl3) 27.5 (CH2, SCH2), 50.7 (CH, CHS), 85.6
νmax(KBr)/cm−1 1732 (CvO), 1264 (C−O); δH (300 MHz, CDCl3) (CH, CHO), 127.2, 128.0, 128.5, 128.7 (CH, ArCH), 135.9, 137.0
1.38–1.94 (9H, m, CH2ring), 2.05–2.22 (1H, m, one of CH2ring), (C), 167.7 (CvO). Found (HRMS, EI): m/z 270.0707. C16H14O2S
3.14 (1H, overlapping ddd appears as dt, J 9.8, 9.8, 3.0, CHS), requires M+ 270.0715; 270 (M+, 5%), 228 (41), 180 (11),
3.22 (1H, A of ABq, J 14.7, SCH2), 3.68 (1H, B of ABq, J 14.5, 122 (38), 98 (90), 91 (11), 77 (11), 67 (100), 43 (92).
SCH2), 4.17–4.37 (1H, m, CHO); δC (75.5 MHz, CDCl3) 22.0,
cis-6-Methyl-5-phenyl-[1,4]oxathian-2-one 27. From trans-
25.5, 27.27, 27.31, 30.8 (5 × CH2ring), 33.5 (SCH2), 46.3 (CHS), methylstyrene oxide 17 (1.01 g, 7.40 mmol); pure product
85.4 (CHO), 168.9 (CvO). Found (HRMS, ESI+): m/z 187.0779. colourless oil (1.40 g, 91%); νmax(film)/cm−1 1739 (CvO);
C9H14O2S [M + H]+ requires M+ 187.0793; 187 [(M + H)+, 40%], δH (300 MHz, CDCl3) 1.18 (3H, d, J 6.3, CH3), 3.35 (1H, A of
95 (100), 42 (58). Note: More recently, it has been found that ABq, J 14.5, one of SCH2), 3.80 (1H, B of ABq, J 14.5, one of
use of a single sodium bicarbonate solution wash leads to SCH2), 4.31 (1H, d, J 3.4, CHS), 4.80 (1H, qd, J 6.3, 3.5, CHO),
better yields (∼47%).
7.23–7.37 (5H, m, aromatic); δC (75.5 MHz, CDCl3) 18.8 (CH3),
cis-5,6-Dimethyl-[1,4]oxathian-2-one 23.58 From trans-2,3- 27.8 (CH2, SCH2), 48.0 (CH, CHS), 77.0 (CH, CHO), 128.6,
dimethyl-oxirane 13 (1.21 mL, 13.86 mmol); purification by 128.7, 128.9, 129.4, 129.9 (CH, phenyl), 137.3 (C), 169.2
column chromatography (ethyl acetate–hexane 20 : 80) gave a (CvO). Found (HRMS, EI): m/z 208.0583. C11H12O2S requires
1716 | Org. Biomol. Chem., 2013, 11, 1706–1725
This journal is © The Royal Society of Chemistry 2013