Chapter II. Synthesis of α,β-unsaturated ketones through nickel-catalysed aldehyde-free
2.5. Experimental
2.5.2. Preparation of Thioesters
Thioesters were prepared according to the literature methods.45–49
Scheme 2.1. Synthesis of S-(Pyridin-2-yl) 4-Methoxybenzothioate (S1)
General procedure for synthesizing a thioester (GP-I): To the solution of 2-mercaptopyridine (1.0 g, 9.0 mmol, 1.0 equiv) in DCM (30 mL), 4-methoxybenzoyl chloride (1.8 g, 10.8 mmol, 1.2 equiv) and TEA (1.4 g, 13.5 mmol, 1.5 equiv) were added. The reaction mixture was stirred for 1 h at room temperature. After completion of the reaction, the mixture was diluted with additional DCM (100 mL), and washed with saturated aqueous NaHCO3 solution (50 mL 2) and brine (50 mL 2). The organic layer was dried over anhydrous Na2SO4 and concentrated in vacuo. The residue was purified by flash column chromatography (hexane/EtOAc = 1:1) to afford the title compound S1 (a white solid, 1.38 g, 63%).
Scheme 2.2. Synthesis of S-(Pyridin-2-yl) Cyclopropanecarbothioate (S28)
General procedure for synthesizing a thioester (GP-II): In a 5-dram vial equipped with a magnetic
stir bar, 2,2′-dipyridyl disulfide (242 mg, 1.1 mmol, 1.1 equiv) and PPh3 (289 mg, 1.1 mmol, 1.1 equiv) were dissolved in DCM (10 mL). Cyclopropanecarboxylic acid (86 mg, 1.0 mmol, 1.0 equiv) was then added to the solution. The reaction mixture was stirred for 1 h at room temperature. After completion of the reaction, the mixture was diluted with additional DCM (50 mL) and washed with saturated aqueous NaHCO3 solution (30 mL 2) and brine (30 mL 2). The organic layer was dried over anhydrous Na2SO4 and concentrated in vacuo. The residue was purified by flash column chromatography (hexane/EtOAc = 1:1) to afford the title compound S28 (a yellow oil, 148 mg, 83%).
S-(Pyridin-2-yl) 4-methoxybenzothioate (S1)3: method GP-I; a white solid (1.38 g, 63%); 1H NMR (400 MHz, CDCl3)δ 8.67 (ddd, J = 4.8, 1.9, 0.9 Hz, 1H), 8.00 (d, J = 9.0 Hz, 2H), 7.78 (td, J = 7.6, 1.9 Hz, 1H), 7.72 (dt, J = 7.9, 1.2 Hz, 1H), 7.32 (ddd, J = 7.3, 4.9, 1.4 Hz, 1H), 6.97 (d, J = 8.9 Hz, 2H), 3.89 (s, 3H).
S-(Pyridin-2-yl) benzothioate (S2)33: method GP-I; a yellow solid (839 mg, 87%); 1H NMR (400 MHz, CDCl3)δ 8.69 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 8.03 (dd, J = 8.4, 1.2 Hz, 2H), 7.81 (td, J = 7.6, 1.9 Hz, 1H), 7.74 (dt, J = 7.9, 1.1 Hz, 1H), 7.65 – 7.60 (m, 1H), 7.50 (t, J
= 7.7 Hz, 2H), 7.35 (ddd, J = 7.4, 4.9, 1.3 Hz, 1H).
S-(Pyridin-2-yl) 4-methylbenzothioate (S3)46: method GP-I; a yellow solid (913 mg, 89%); 1H NMR (400 MHz, CDCl3)δ 8.68 (d, J = 5.8 Hz, 1H), 7.92 (d, J = 8.2 Hz, 2H), 7.79 (td, J
= 7.6, 1.9 Hz, 1H), 7.73 (d, J = 7.8 Hz, 1H), 7.33 (ddd, J = 7.2, 4.9, 1.2 Hz, 1H), 7.29 (d, J = 8.0 Hz, 2H), 2.44 (s, 3H).
S-(Pyridin-2-yl) 4-ethylbenzothioate (S4)47: method GP-I; a white solid (920 mg, 84%); 1H NMR (400 MHz, CDCl3) δ 8.67 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 7.94 (d, J = 8.3 Hz, 2H), 7.78 (td, J = 7.6, 1.9 Hz, 1H), 7.73 (dt, J = 7.8, 1.1 Hz, 1H), 7.36 – 7.28 (m, 3H), 2.72 (q, J = 7.6 Hz, 2H), 1.27 (t, J = 7.6 Hz, 3H).
S-(Pyridin-2-yl) 4-isopropylbenzothioate (S5): method GP-I; a white solid (260 mg, 37%); m.p.
92 ℃; 1H NMR (400 MHz, CDCl3) δ 8.67 (ddd, J = 4.8, 2.0, 0.9 Hz, 1H), 7.96 (d, J = 8.4 Hz, 2H), 7.78 (td, J = 7.6, 1.9 Hz, 1H), 7.73 (dt, J = 7.9, 1.2 Hz, 1H), 7.38 – 7.29 (m, 3H), 2.98 (m, 1H), 1.28 (d, J = 6.9 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 189.0, 155.8, 151.8, 150.6, 137.2, 134.5, 131.0, 128.0, 127.1, 123.7, 34.5, 23.8; HRMS (ESI):
m/z [M+H]+ calcd for (C15H16NOS+): 258.09471, found: 258.09467.
S-(Pyridin-2-yl) 4-(tert-butyl)benzothioate (S6)48: method GP-I; a white solid (102 mg, 38%); 1H NMR (400 MHz, CDCl3)δ 8.68 (ddd, J = 4.8, 1.9, 0.9 Hz, 1H), 7.96 (d, J = 8.6 Hz, 2H), 7.79 (td, J = 7.6, 1.9 Hz, 1H), 7.73 (dt, J = 7.9, 1.2 Hz, 1H), 7.51 (d, J = 8.6 Hz, 2H), 7.33 (ddd, J = 7.3, 4.8, 1.4 Hz, 1H), 1.36 (s, 9H).
S-(Pyridin-2-yl) [1,1'-biphenyl]-4-carbothioate (S7): method GP-I; a white solid (707 mg, 90%);
m.p. 154 ℃; 1H NMR (400 MHz, CDCl3) δ 8.70 (d, J = 3.9 Hz, 1H), 8.10 (d, J = 8.4 Hz, 2H), 7.81 (td, J = 7.6, 1.9 Hz, 1H), 7.76 (d, J = 7.6 Hz, 1H), 7.72 (d, J = 8.6 Hz, 2H), 7.64 (d, J = 7.2 Hz, 2H), 7.49 (t, J = 7.4 Hz, 2H), 7.42 (t, J = 7.3 Hz, 1H), 7.35 (ddd, J = 7.2, 4.9, 1.3 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 189.0, 151.5, 150.7, 146.8, 139.8, 137.3, 135.4, 131.0, 129.2, 128.6, 128.3, 127.6, 127.4, 123.8; HRMS (ESI): m/z [M+H]+ calcd for (C18H14NOS+): 292.07906, found: 292.07892.
S-(Pyridin-2-yl) 4-ethoxybenzothioate (S8): method GP-I; a white solid (619 mg, 53%); m.p. 91 ℃;
1H NMR (400 MHz, CDCl3) δ 8.67 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 7.99 (d, J = 8.9 Hz, 2H), 7.78 (td, J = 7.6, 1.9 Hz, 1H), 7.73 (dt, J = 7.9, 1.1 Hz, 1H), 7.32 (ddd, J
= 7.3, 4.8, 1.4 Hz, 1H), 6.95 (d, J = 8.9 Hz, 2H), 4.12 (q, J = 7.0 Hz, 2H), 1.45 (t, J = 7.0 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 187.8, 163.8, 151.9, 150.5, 137.2, 131.1, 130.0, 129.2, 123.6, 114.6, 64.1, 14.8; HRMS (ESI): m/z [M+H]+ calcd for (C14H14NO2S+): 260.07398, found:
260.07388.
S-(Pyridin-2-yl) 4-(benzyloxy)benzothioate (S9): method GP-I; a white solid (466 mg, 54%); m.p.
127 ℃; 1H NMR (400 MHz, CDCl3) δ 8.67 (ddd, J = 4.8, 1.9, 0.9 Hz, 1H), 8.00 (d, J = 8.8 Hz, 2H), 7.78 (td, J = 7.6, 1.9 Hz, 1H), 7.72 (d, J = 7.9 Hz, 1H), 7.46 – 7.40 (m, 4H), 7.39 – 7.35 (m, 1H), 7.32 (ddd, J = 7.3, 4.9, 1.4 Hz, 1H), 7.04 (d, J
= 8.8 Hz, 2H), 5.15 (s, 2H);13C NMR (100 MHz, CDCl3) δ 187.9, 163.5, 151.8, 150.6, 137.2, 136.1, 131.1, 130.0, 129.6, 128.9, 128.5, 127.7, 123.6, 115.0, 70.4; HRMS (ESI): m/z [M+H]+ calcd for (C19H16NO2S+): 322.08963, found: 322.08942.
S-(Pyridin-2-yl) 4-phenoxybenzothioate (S10): method GP-II; a white solid (271 mg, 88%); m.p.
83 ℃; 1H NMR (400 MHz, CDCl3) δ 8.67 (ddd, J = 4.9, 1.9, 1.0 Hz, 1H), 8.00 (d, J = 8.9 Hz, 2H), 7.78 (td, J = 7.6, 1.8 Hz, 1H), 7.72 (dt, J = 7.9, 1.1 Hz, 1H), 7.44 – 7.38 (m, 2H), 7.33 (ddd, J = 7.3, 4.8, 1.3 Hz, 1H), 7.22 (t, J = 7.4 Hz, 1H), 7.09 (dd, J = 8.6, 1.1 Hz, 2H), 7.02 (d, J = 8.8 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 188.0, 162.9, 155.3, 151.6, 150.6, 137.3, 131.0, 131.0, 130.3, 130.0, 125.0, 123.7, 120.5, 117.5; HRMS (ESI): m/z [M+H]+ calcd for (C18H14NO2S+): 308.07398, found: 308.07382.
S-(Pyridin-2-yl) 4-hydroxybenzothioate (S11): method GP-II; a white solid (180 mg, 78%); m.p.
156 ℃; 1H NMR (400 MHz, DMSO-d6) δ 10.68 (br, 1H), 8.63 (ddd, J = 4.8, 2.0, 0.9 Hz, 1H), 7.92 (td, J = 7.7, 1.9 Hz, 1H), 7.86 (d, J = 8.8 Hz, 2H), 7.72 (d, J = 7.8 Hz, 1H), 7.47 (ddd, J = 7.6, 4.9, 1.2 Hz, 1H), 6.93 (d, J = 8.8 Hz, 2H); 13C NMR (100 MHz, DMSO-d6) δ 186.6, 163.2, 150.8, 150.4, 137.6, 131.0, 129.8, 126.9, 124.0, 115.8;
HRMS (ESI): m/z [M+H]+ calcd for (C12H10NO2S+): 232.04268, found: 232.04259.
S-(Pyridin-2-yl) 4-fluorobenzothioate (S12): method GP-I; a white solid (150 mg, 64%); m.p. 90 ℃;
1H NMR (400 MHz, CDCl3) δ 8.68 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 8.05 (dd, J = 8.9, 5.3 Hz, 2H), 7.80 (td, J = 7.7, 1.9 Hz, 1H), 7.72 (dt, J = 7.8, 1.1 Hz, 1H), 7.35 (ddd, J = 7.5, 4.9, 1.2 Hz, 1H), 7.18 (t, J = 8.6 Hz, 2H); 19F NMR (377 MHz, CDCl3) δ - 103.5; 13C NMR (100 MHz, CDCl3)δ 188.0, 166.4 (d, J = 255.9 Hz), 151.2, 150.7, 137.4, 133.0 (d, J
= 3.2 Hz), 131.0, 130.3 (d, J = 9.5 Hz), 123.9, 116.2 (d, J = 22.2 Hz); HRMS (ESI): m/z [M+H]+ calcd for (C12H9FNOS+): 234.03834, found: 234.03830.
S-(Pyridin-2-yl) 4-chlorobenzothioate (S13)33: method GP-I; a white solid (744 mg, 66%); 1H NMR (400 MHz, CDCl3) δ 8.69 (ddd, J = 4.8, 1.9, 0.9 Hz, 1H), 7.96 (d, J = 8.8 Hz, 2H), 7.80 (td, J = 7.7, 1.9 Hz, 1H), 7.72 (dt, J = 7.8, 1.1 Hz, 1H), 7.48 (d, J = 8.8 Hz, 2H), 7.35 (ddd, J = 7.5, 4.9, 1.2 Hz, 1H).
S-(Pyridin-2-yl) 4-bromobenzothioate(S14)46: method GP-I; a white solid (988 mg, 75%); 1H NMR (400 MHz, CDCl3) δ 8.68 (ddd, J = 4.9, 2.0, 0.9 Hz, 1H), 7.88 (d, J = 8.6 Hz, 2H), 7.80 (td, J = 7.7, 1.9 Hz, 1H), 7.72 (dt, J = 7.9, 1.1 Hz, 1H), 7.64 (d, J = 8.6 Hz, 2H), 7.35 (ddd, J = 7.5, 4.8, 1.2 Hz, 1H).
Methyl 4-((pyridin-2-ylthio)carbonyl)benzoate (S15): method GP-I; a white solid (105 mg, 38%);
m.p. 120 ℃; 1H NMR (400 MHz, CDCl3) δ 8.70 (ddd, J = 4.8, 1.9, 0.9 Hz, 1H), 8.16 (d, J = 8.7 Hz, 2H), 8.07 (d, J = 8.7 Hz, 2H), 7.82 (td, J = 7.7, 1.9 Hz, 1H), 7.74 (dt, J = 7.9, 1.1 Hz, 1H), 7.37 (ddd, J = 7.5, 4.9, 1.2 Hz, 1H), 3.96 (s, 3H);
13C NMR (100 MHz, CDCl3)δ 189.1, 166.1, 150.9, 150.8, 140.0, 137.5, 134.8, 131.0, 130.2, 127.6, 124.0, 52.7; HRMS (ESI): m/z [M+H]+ calcd for (C14H12NO3S+): 274.05324, found: 274.05301.
S-(Pyridin-2-yl) 4-(trifluoromethyl)benzothioate (S16)33:method GP-I; a white solid (185 mg, 65%);
1H NMR (400 MHz, CDCl3) δ 8.70 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 8.13 (d, J = 8.1 Hz, 2H), 7.82 (td, J = 7.7, 1.9 Hz, 1H), 7.77 (d, J = 8.2 Hz, 2H), 7.74 (dt, J = 7.9, 1.0 Hz, 1H), 7.38 (ddd, J = 7.6, 4.8, 1.2 Hz, 1H).
S-(Pyridin-2-yl) 3-methylbenzothioate (S17): method GP-I; a yellow oil (861 mg, 84%); 1H NMR (400 MHz, CDCl3) δ 8.68 (ddd, J = 4.9, 1.9, 1.0 Hz, 1H), 7.84 (s, 1H), 7.82 – 7.81 (m, 1H), 7.79 (td, J = 7.6, 1.9 Hz, 1H), 7.73 (dt, J = 7.9, 1.1 Hz, 1H), 7.43 (d, J = 7.2 Hz, 1H), 7.40 – 7.35 (m, 1H), 7.33 (ddd, J = 7.4, 4.9, 1.3 Hz, 1H), 2.43 (s, 3H);
13C NMR (100 MHz, CDCl3)δ 189.6, 151.6, 150.6, 138.9, 137.3, 136.7, 134.8, 131.0, 128.8, 128.1, 124.9, 123.7, 21.5; HRMS (ESI): m/z [M+H]+ calcd for (C13H12NOS+): 230.06341, found: 230.06331.
S-(Pyridin-2-yl) 3-methoxybenzothioate (S18)33: method GP-I; a yellow oil (1.3 g, 98%); 1H NMR (400 MHz, CDCl3) δ 8.68 (ddd, J = 4.9, 2.0, 0.9 Hz, 1H), 7.80 (td, J = 7.6, 1.9 Hz, 1H), 7.73 (dt, J = 8.0, 1.1 Hz, 1H), 7.64 (dt, J = 7.7, 1.1 Hz, 1H), 7.51 (dd, J = 2.6, 1.6 Hz, 1H), 7.40 (t, J = 8.0 Hz, 1H), 7.34 (ddd, J = 7.4, 4.8, 1.3 Hz, 1H), 7.16 (ddd, J = 8.3, 2.6, 0.9 Hz, 1H), 3.86 (s, 3H).
S-(Pyridin-2-yl) 3-ethoxybenzothioate (S19): method GP-II; a colorless oil (161 mg, 62%); 1H NMR (400 MHz, CDCl3) δ 8.68 (d, J = 4.8 Hz, 1H), 7.79 (td, J = 7.6, 1.8 Hz, 1H), 7.72 (d, J = 7.9 Hz, 1H), 7.62 (d, J = 7.7 Hz, 1H), 7.49 (s, 1H), 7.39 (t, J = 8.0 Hz, 1H), 7.36 – 7.31 (m, 1H), 7.14 (dd, J = 8.3, 2.6 Hz, 1H), 4.08 (q, J = 6.9 Hz, 2H), 1.44 (t, J = 7.0 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 189.4, 159.3, 151.5, 150.7, 138.0, 137.3, 131.0, 130.0, 123.8, 121.0, 120.1, 112.5, 63.9, 14.9; HRMS (ESI): m/z [M+H]+ calcd for (C14H14NO2S+):
260.07398, found: 260.07382.
S-(Pyridin-2-yl) 2-methoxybenzothioate (S20)33: method GP-I; a yellow oil (472 mg, 71%); 1H NMR (400 MHz, CDCl3) δ 8.65 (ddd, J = 4.8, 1.8, 1.1 Hz, 1H), 7.85 (dd, J = 8.0, 1.6 Hz, 1H), 7.77 – 7.71 (m, 2H), 7.54 – 7.47 (m, 1H), 7.29 (ddd, J = 6.7, 4.9, 2.0 Hz, 1H), 7.04 – 7.00 (m, 2H), 3.95 (s, 3H).
S-(Pyridin-2-yl) 2-ethoxybenzothioate (S21):method GP-II; a yellow oil (227 mg, 87%); 1H NMR (400 MHz, CDCl3) δ 8.67 (d, J = 6.6 Hz, 1H), 7.87 (dd, J = 8.2, 1.8 Hz, 1H), 7.77 (td, J = 7.5, 1.9 Hz, 1H), 7.72 (dt, J = 7.8, 1.2 Hz, 1H), 7.51 – 7.45 (m, 1H), 7.30 (ddd, J = 7.2, 4.9, 1.5 Hz, 1H), 7.04 – 6.96 (m, 2H), 4.23 (q, J = 7.0 Hz, 2H), 1.56 (t, J = 7.0 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 188.3, 158.2, 152.9, 150.4, 137.1, 134.5, 131.1, 130.2, 126.2, 123.5, 120.6, 113.1, 65.1, 14.9; HRMS (ESI): m/z [M+H]+ calcd for (C14H14NO2S+): 260.07398, found:
260.07391.
S-(Pyridin-2-yl) 2-methylbenzothioate (S22): method GP-I; a yellow oil (631 mg, 61%); 1H NMR (400 MHz, CDCl3)δ 8.70 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 7.95 (dd, J = 7.8, 1.4 Hz, 1H), 7.80 (td, J = 7.7, 1.9 Hz, 1H), 7.73 (dt, J = 7.9, 1.1 Hz, 1H), 7.44 (td, J = 7.5, 1.3 Hz, 1H), 7.36 – 7.26 (m, 3H), 2.51 (s, 3H); 13C NMR (100 MHz, CDCl3)δ 191.3, 152.0, 150.6, 137.8, 137.4, 136.6, 132.4, 132.0, 130.9, 129.0, 126.1, 123.8, 20.9; HRMS (ESI): m/z [M+H]+ calcd for (C13H12NOS+): 230.06341, found: 230.06334.
S-(Pyridin-2-yl) naphthalene-2-carbothioate (S23)33: method GP-I; a white solid (794 mg, 67%); 1H NMR (400 MHz, CDCl3) δ 8.71 (ddd, J = 4.9, 1.9, 1.0 Hz, 1H), 8.62 (s, 1H), 8.04 – 8.00 (m, 2H), 7.93 (d, J = 8.8 Hz, 1H), 7.90 (d, J = 8.3 Hz, 1H), 7.85 – 7.80 (m, 1H), 7.78 (dt, J = 7.9, 1.6 Hz, 1H), 7.66 – 7.57 (m, 2H), 7.36 (ddd, J = 7.0, 4.8, 1.6
Hz, 1H).
S-(Pyridin-2-yl) naphthalene-1-carbothioate (S24): method GP-I; a yellow solid (569 mg, 79%);
m.p. 55 ℃; 1H NMR (400 MHz, CDCl3) δ 8.74 – 8.70 (m, 1H), 8.55 (d, J = 8.0 Hz, 1H), 8.24 (dd, J = 7.3, 1.2 Hz, 1H), 8.06 (d, J = 8.3 Hz, 1H), 7.90 (dd, J = 7.5, 2.0 Hz, 1H), 7.87 – 7.81 (m, 2H), 7.62 – 7.53 (m, 3H), 7.37 (ddd, J = 6.0, 4.9, 2.6 Hz, 1H); 13C NMR (100 MHz, CDCl3) δ 191.4, 152.0, 150.7, 137.4, 134.5, 133.9, 133.7, 130.8, 129.4, 128.5, 128.5, 128.3, 126.9, 125.3, 124.6, 123.8; HRMS (ESI): m/z [M+H]+ calcd for (C16H12NOS+):
266.06341, found: 266.06320.
S-(Pyridin-2-yl) pyridine-2-carbothioate (S25)33:method GP-II; a white solid (101 mg, 38%); 1H NMR (400 MHz, CDCl3) δ 8.66 (ddd, J = 4.9, 1.9, 1.0 Hz, 1H), 8.27 – 8.21 (m, 1H), 7.98 (s, 1H), 7.83 – 7.80 (m, 1H), 7.80 – 7.75 (m, 1H), 7.38 – 7.28 (m, 4H), 3.88 (s, 3H).
S-(Pyridin-2-yl) 2,2-dimethylpropanethioate (S26): method GP-I; a yellow oil (843 mg, 96%); 1H NMR (400 MHz, CDCl3) δ 8.63 (ddd, J = 4.9, 1.9, 0.9 Hz, 1H), 7.73 (td, J = 7.7, 1.9 Hz, 1H), 7.56 (dt, J = 7.9, 1.0 Hz, 1H), 7.28 (ddd, J = 7.7, 5.0, 1.3 Hz, 1H), 1.33 (s, 9H); 13C NMR (100 MHz, CDCl3) δ 203.9, 151.9, 150.5, 137.2, 131.0, 123.5, 47.5, 27.5; HRMS (ESI): m/z [M+H]+ calcd for (C10H14NOS+): 196.07906, found: 196.07903.
S-(Pyridin-2-yl) pentanethioate (S27)49:method GP-I; a yellow oil (483 mg, 55%); 1H NMR (400 MHz, CDCl3) δ 8.62 (ddd, J = 4.8, 2.0, 0.9 Hz, 1H), 7.73 (td, J = 7.7, 1.9 Hz, 1H), 7.61 (dt, J = 7.9, 1.1 Hz, 1H), 7.32 – 7.24 (m, 1H), 2.70 (t, J = 7.4 Hz, 2H), 1.78 – 1.65 (m, 2H), 1.48 – 1.32 (m, 2H), 0.93 (t, J = 7.3 Hz, 3H).
S-(Pyridin-2-yl) cyclopropanecarbothioate (S28)37:method GP-II; a yellow oil (148 mg, 83%); 1H NMR (400 MHz, CDCl3) δ 8.62 (ddd, J = 4.9, 2.0, 0.9 Hz, 1H), 7.73 (td, J = 7.7, 1.9 Hz, 1H), 7.63 (dt, J = 7.9, 1.1 Hz, 1H), 7.29 – 7.26 (m, 1H), 2.13 (tt, J = 7.9, 4.5 Hz, 1H), 1.28 – 1.22 (m, 2H), 1.08 – 1.01 (m, 2H).
S-(Pyridin-2-yl) cyclopentanecarbothioate (S29): method GP-II; a yellow oil (177 mg, 85%); 1H NMR (400 MHz, CDCl3) δ 8.61 (ddd, J = 4.9, 2.0, 0.9 Hz, 1H), 7.72 (td, J = 7.7, 1.9 Hz, 1H), 7.61 (dt, J = 7.9, 1.1 Hz, 1H), 7.29 – 7.24 (m, 1H), 3.12 (m, 1H), 2.02 – 1.86 (m, 4H), 1.77 – 1.58 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 200.1, 152.0, 150.5, 137.1, 130.3, 123.5, 53.6, 30.7, 26.0; HRMS (ESI): m/z [M+H]+ calcd for (C11H14NOS+): 208.07906, found: 208.07888.
S-(Pyridin-2-yl) cyclohexanecarbothioate (S30)33: method GP-I; a yellow solid (850 mg, 85%); 1H NMR (400 MHz, CDCl3) δ 8.62 (ddd, J = 4.8, 1.9, 0.9 Hz, 1H), 7.72 (td, J = 7.7, 1.9 Hz, 1H), 7.60 (dt, J = 7.9, 1.0 Hz, 1H), 7.29 – 7.25 (m, 1H), 2.63 (tt, J = 11.4, 3.6 Hz, 1H), 2.07 – 1.99 (m, 2H), 1.86 – 1.78 (m, 2H), 1.71 – 1.64 (m, 1H), 1.59 – 1.48 (m, 2H), 1.38 – 1.21 (m, 3H).