10.1002/adsc.201700532
Advanced Synthesis & Catalysis
128.88, 128.82, 127.67, 127.18, 125.66, 125.34, 51.71,
(brs, 1H), 2.64 (t, J = 7.6 Hz, 2H), 2.08 (t, J = 7.6 Hz, 2H),
1.94 (quin, J = 7.6 Hz, 2H), 1.33 (s, 9H); 13C NMR (100
MHz, CDCl3) δ 171.95, 141.58, 128.44, 128.28, 125.84,
51.03, 36.70, 35.05, 28.78, 27.07; HRMS (ESI) calcd for
C14H22NO [M + H]+ : 220.1696; found: 220.1692.
28.86; HRMS (ESI) calcd for C17H20NO [M + H]+
254.1539; found: 254.1533.
:
2-bromo-N-(tert-butyl)benzamide (3ka): Off-white solid;
1
Yield: 73% (186.98 mg); Mp 99-101 °C; H NMR (400
MHz, CDCl3) δ 7.55 (dd, J = 8.0, 1.2 Hz, 1H), 7.48 (dd, J
= 7.6, 1.6 Hz, 1H), 7.33 (td, J = 7.6, 1.2 Hz, 1H), 7.23 (td,
J = 1.6 Hz, 1H), 5.73 (brs, 1H), 1.47 (s, 9H); 13C NMR
(100 MHz, CDCl3) δ 167.06, 139.15, 133.30, 130.95,
129.42, 127.64, 119.24, 52.39, 28.89; HRMS (ESI) calcd
for C11H15NOBr [M + H]+ : 256.0332; found: 256.0330.
N-(tert-butyl)-2-(4-fluorophenoxy)acetamide (3ta): Pale
1
yellow solid; Yield: 62% (137.8 mg); Mp °C; H NMR
(400 MHz, CDCl3) δ 7.03-6.98 (m, 2H), 6.88-6.84 (m, 2H),
6.33 (brs, 1H), 4.33 (s, 2H), 1.39 (s, 9H); 13C NMR (100
MHz, CDCl3) δ 167.02, 157.89 (d, JF = 238.3 Hz), 153.30,
116.16 (d, JF =24 Hz), 115.85 (d, JF = 8 Hz), 68.40, 51.25,
28.72; HRMS (ESI) calcd for C12H16NO2FNa [M+Na]+ :
248.1057; found: 248.1058.
N-(tert-butyl)-3-iodobenzamide (3la): White solid; Yield:
1
71% (215.23 mg); Mp 110-111 °C; H NMR (400 MHz,
CDCl3) δ 8.03 (t, J = 1.6 Hz, 1H), 7.79 (ddd, J = 7.6, 1.6,
1.2 Hz, 1H), 7.66 (ddd, J = 8.0, 2.0, 1.2 Hz, 1H), 7.14 (t, J
= 8.0 Hz, 1H), 5.90 (brs, 1H), 1.46 (s, 9H); 13C NMR (100
MHz, CDCl3) δ 165.25, 139.89, 137.91, 135.73, 130.11,
125.92, 94.15, 51.84, 28.77; HRMS (ESI) calcd for
C11H15NOI [M + H]+ : 304.0193; found: 304.0191.
General procedure for the synthesis of compounds 5aa-
5la. In a 15 mL oven dried sealed tube was charged with
respective β-ketonitrile 4a-l (1.0 mmol) in 1,2-
dichoroethane (DCE, 0.5 mL) and stirred the solution at
0 °C. To the solution was added BF3-etherate (4.0 mmol)
drop wise for around 1 min. at 0 °C and maintained stirring
at same temperature for 10 min. To the same solution was
added 70% aq. TBHP solution 2a (2.4 mmol) drop wise
and continued the stirring at same temperature for 30 min.
Further, the resultant reaction mixture was stirred at room
temperature and then at 65 °C. The reaction was monitored
by TLC until the completion. The reaction mass was
cooled to room temperature and quenched with aq. K2CO3.
The aqueous layer was extracted with EA (3X10 mL), and
combined organic layer was washed with aq. K2CO3 (1X10
mL) followed by water (2X10 mL) and brine solution. The
final solution was dried over Na2SO4 and concentrated
under reduced pressure. Finally, the resultant crude was
purified by column chromatography using 5-20%
EA/hexane to obtain the pure compounds 5aa-la.
4-acetyl-N-(tert-butyl)benzamide (3ma): White solid;
1
Yield: 69% (151.3 mg); Mp 106-108 °C; H NMR (400
MHz, CDCl3) δ 7.98 (d, J = 8.8 Hz, 2H), 7.79 (d, J = 8.8
Hz, 2H), 6.01 (brs, 1H), 2.62 (s, 3H), 1.48 (s, 9H); 13C
NMR (100 MHz, CDCl3) δ 197.42, 165.86, 139.79, 138.80,
130.11, 128.41, 128.24, 126.99, 51.92, 28.77, 26.76;
HRMS (ESI) calcd for C13H18NO2 [M + H]+ : 220.1332;
found: 220.1331.
N-(tert-butyl)-4-(trifluoromethyl)benzamide
(3na):
1
White solid; Yield: 63% (154.5 mg); Mp 148-150 °C; H
NMR (400 MHz, CDCl3) δ 7.82 (dd, J = 8.4 Hz, 2H), 7.66
(d, J = 8.0 Hz, 2H), 5.97 (brs, 1H), 1.48 (s, 9H); 13C NMR
(100 MHz, CDCl3) δ 165.59, 139.19, 132.80 (q, JCF3 = 33
Hz), 127.16, 125.49 (q, JCF3 = 3.7 Hz) 125.03, 122.32,
51.98, 28.76; HRMS (ESI) calcd for C12H15NOF3 [M +
H]+ : 246.1100; found: 246.1096.
(Z)-N-(tert-butyl)-3-((difluoroboranyl)oxy)-3-
phenylacrylamide (5aa): White solid; Yield: 67% (178.95
mg); Mp 191-193 °C; 1H NMR (400 MHz, CDCl3) δ 7.84-
7.81 (m, 2H), 7.47 (ddd, J = 8.0, 4.0, 2.0 Hz, 1H), 7.39-
7.33 (m, 2H), 6.25 (brs, 1H), 5.81 (s, 1H), 1.48 (s, 9H); 13C
NMR (100 MHz, CDCl3) δ 172.21, 169.16, 133.01, 132.15,
128.54, 126.87, 85.13, 54.58, 28.89; HRMS (ESI) calcd for
C13H17BNO2F2 [M + H]+ : 268.13149; found: 268.13144.
N-(tert-butyl)-4-nitrobenzamide (3oa): Off-white solid;
1
Yield: 67% (148.9 mg); Mp 153-155 °C; H NMR (400
MHz, CDCl3) δ 8.24 (d, J = 7.6 Hz, 2H), 7.87 (d, J = 7.6
Hz, 2H), 6.06 (brs, 1H), 1.49 (s, 9H); 13C NMR (100 MHz,
CDCl3) δ 164.82, 149.26, 141.49, 127.88, 123.66, 52.24,
28.69; HRMS (ESI) calcd for C11H14N2O3Na [M + Na]+ :
245.0896; found: 245.0898.
(Z)-N-(tert-butyl)-3-((difluoroboranyl)oxy)-3-(p-
tolyl)acrylamide (5ba): Pale yellow solid; Yield: 71%
(199.59 mg); Mp 260-262 °C; 1H NMR (400 MHz,
CDCl3+DMSO-d6) δ 8.32 (brs, 1H), 7.70 (d, J = 8.4 Hz,
2H), 7.21 (d, J = 8.0 Hz, 2H), 5.91 (s, 1H), 2.39 (s, 3H),
1.48 (s, 9H); 13C NMR (100 MHz, CDCl3) δ 170.24,
168.59, 141.98, 130.49, 128.91, 126.32, 84.84, 53.44,
28.60, 21.20; HRMS (ESI) calcd for C14H19BNO2F2 [M +
H]+ : 282.14714; found: 282.14716.
(E)-N-(tert-butyl)cinnamamide (3pa): White solid;
1
Yield: 92% (187.02 mg); Mp 140-142 °C; H NMR (400
MHz, CDCl3) δ 7.57 (d, J = 15.6 Hz, 1H), 7.46-7.44 (m,
2H), 7.36-7.26 (m, 3H), 6.35 (d, J = 15.6 Hz, 1H), 5.59
(brs, 1H), 1.43 (s, 9H); 13C NMR (100 MHz, CDCl3) δ
165.21, 140.20, 134.99, 129.42, 128.74, 127.68, 122.02,
51.50, 28.88; HRMS (ESI) calcd for C13H17NONa [M +
Na]+ : 226.1202; found: 226.1203.
(Z)-N-(tert-butyl)-3-(4-(tert-butyl)phenyl)-3-
((difluoroboranyl)oxy)acrylamide (5ca): Pale yellow
1
solid; Yield: 69% (223 mg); Mp 211-214 °C ; H NMR
(E)-N-(tert-butyl)-3-cyanoacrylamide (3qa): White solid;
(400 MHz, CDCl3) δ 7.77 (d, J = 8.4 Hz, 2H), 7.39 (d, J =
8.8 Hz, 2H), 6.25 (brs, 1H), 5.80 (s, 1H), 1.47 (s, 9H), 1.30
(s, 9H); 13C NMR (100 MHz, CDCl3) δ 172.26, 169.21,
155.91, 130.21, 126.79, 125.52, 84.57, 54.44, 34.99, 31.07,
28.92; HRMS (ESI) calcd for C17H25BNO2F2 [M + H]+ :
324.1941; found: 324.1942.
1
Yield: 52% (79.14 mg); Mp 118-121 °C; H NMR (400
MHz, CDCl3) δ 6.68 (d, J = 16.0 Hz, 1H), 6.44 (d, J = 15.6
Hz, 1H), 5.72 (brs, 1H), 1.40 (s, 9H); 13C NMR (100 MHz,
CDCl3) δ 160.68, 143.40, 116.30, 109.13, 52.39, 28.52;
HRMS (ESI) calcd for C8H13N2O [M + H]+ : 153.1022;
found: 153.1020.
(Z)-N-(tert-butyl)-3-((difluoroboranyl)oxy)-3-(4-
N-(tert-butyl)-2-phenylacetamide (3ra): White solid;
methoxyphenyl)acrylamide (5da): Off-white solid;
1
1
Yield: 82% (156.84 mg); Mp 112-113 °C; H NMR (400
Yield: 61% (181.24 mg); Mp 251-252 °C; H NMR (400
MHz, CDCl3) δ 7.34 (ddd, J = 8.4, 6.8, 0.8 Hz, 2H), 7.29-
7.26 (m, 1H), 7.25-7.22 (m, 2H), 5.20 (brs, 1H), 3.48 (s,
2H), 1.28 (s, 9H); 13C NMR (100 MHz, CDCl3) δ 170.24,
135.48, 129.26, 128.90, 127.12, 51.23, 44.89, 28.67;
HRMS (ESI) calcd for C12H18NO [M + H]+ : 192.1383;
found: 192.1379.
MHz, CDCl3) δ 7.80 (d, J = 8.8 Hz, 2H), 6.89 (d, J = 8.8
Hz, 2H), 5.94 (brs, 1H), 5.66 (s, 1H), 3.84 (s, 3H), 1.48 (s,
9H); 13C NMR (100 MHz, CDCl3) δ 172.25, 169.20,
162.96, 128.88, 113.91, 83.39, 55.42, 54.43, 29.03; HRMS
(ESI) calcd for C14H17BNO3F2 [M - H]+ : 296.1264; found:
298.1271.
N-(tert-butyl)-4-phenylbutanamide (3sa): White solid;
(Z)-N-(tert-butyl)-3-((difluoroboranyl)oxy)-3-(3-
1
Yield: 79% (173.27 mg); Mp 68-70 °C; H NMR (400
methoxyphenyl)acrylamide (5ea): White solid; Yield:
1
MHz, CDCl3) δ 7.30-7.25 (m, 2H), 7.20-7.16 (m, 3H), 5.24
60% (178.27 mg); Mp 222-224 °C; H NMR (400 MHz,
5
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